“This.” I point at the wrinkle. “This vast wrinkle between my eyebrows. As well as my whole forehead, the line down the side of my face, the myriad lines around my eyes, the lines just starting to form above my lips. In fact, my lips are horrible, far too small. Shall I go on?”

Brenda is a delicate lady of Asian descent and totally wrinkle-free. She could be aged anywhere between 25 and 40 – I have no idea – but it’s a look I am keen to emulate. Brenda came to England in 1993 and has been working in antiageing treatments ever since. She was one of the first nurses in the UK to practise Botox, so she has been doing it for more than nine years. Some say that the treatment can make you look frozen, but Brenda says that this is not the fault of the Botox, rather the person who has administered it. According to various websites, the possible side effects include headaches, flu-like symptoms, temporary eyelid droop, nausea, double vision, facial pain, redness at the injection site and muscle weakness. So, at worst, I will be a vomiting, sneezing lunatic. But at least I’ll be wrinkle-free.

Brenda asks me to frown, then smile. “The lines you have could be treated with botulinum toxin,” she says. I feel my heart skip a beat, like a teenager hearing the name of her secret boyfriend. “You mentioned something about your lips?”

“I hate them – they’re too thin. But I don’t want a trout pout.” “I think you should do the upper face with Botox, then have filler to lift the corners of your mouth. That way, you keep the cost down as well,” she says.

Ah yes, the cost. Staying young doesn’t come cheap. If I’d known, I would have avoided laughing all my life; now, I can just be miserable paying for it. The fillers are £250 each and the Botox injections £200 each.

“But, you know, there is no point in just coming in and having a one-off treatment,” says Brenda. “This is a work in progress, and you have to maintain your Botox to get the best out of it.”

I sit there thinking for a few minutes. The downside could be any of the side effects I mentioned earlier, along with a very grumpy husband. The upside will be a wrinkle-free me. “Let’s do the Botox and the fillers to lift the mouth, but not the lips,” I say to Brenda.

Wednesday, 12.30pm, on the couch

My husband’s words, “You need braintox, not Botox”, are echoing in my head as I watch Brenda prepare the treatment. If it all goes horribly wrong, I’m in deep trouble. Not only will Rupert hate me and think I’m even more stupid than he does now, but I could end up with a rash over my face or a drooping eye.

Brenda has taken a series of Polaroids of me, so we can do a before and after. For the pictures, I have to smile, frown and raise my eyebrows. Consequently, I look quite mad. Whatever happens today, it’s not possible to look any worse than that.

“Frown for me,” says Brenda, needle in hand. She pinches a piece of my skin. “It’s a tiny needle and only the tip goes in, so it shouldn’t hurt too much.”

After about 10 minutes, all the Botox is done. Amazingly, I hardly feel a thing.

“Now, don’t touch it, but you’re to keep frowning, smiling and raising your eyebrows every few minutes for the next two hours. Don’t lie flat for six hours, and no strenuous exercise for six hours. Now for the fillers.”

Brenda injects the side of my face; it doesn’t hurt at all. “Okay, take a look,” she says, handing me a mirror.

“I can see specks of blood,” I say, suddenly feeling quite weak. “Compare it with the other side.” I have to admit, it is amazing. I can see that the left side of my face looks younger. It’s lifted the entire area.

This is a transformation, and it’s taken all of three seconds. Brenda has achieved something with her needle that no amount of exercise, healthy food or vitamins could do. Why isn’t everyone doing this?

Wednesday, 4.30pm

Am almost arrested for pulling strange faces at the Chanel counter in Harvey Nichols in an effort to keep frowning, smiling and raising my eyebrows, as I was told to. Luckily, when I explain what I’m doing, the girl behind the counter totally understands. She’s been there, done that Botox thing. “Forget face creams,” she whispers.

“Botox is where it’s at.”

Wednesday, 10pm

Am taking off my make-up, no visible change to my forehead, but then, Botox Brenda did say it would take two to three days. Go to bed excited by the thought of what I might look like when I wake up.

Thursday, midday

I have a mild headache, which I take to be a good sign. No vomiting or sneezing yet. But the wrinkle is still there. “You’re not long for this world, buster,” I keep telling it. It doesn’t look worried.

Friday, 10pm

Am jolly pleased with the way I look as I stumble to bed, having drunk half a bottle of champagne and three glasses of pinot grigio. Am staying in Sussex with my friend, Annika. She is a former model and really too beautiful to be friends with, but too amusing not to be. Maybe not the best person to be around when you’re in the middle of an antiageing procedure. I fall into bed praying the Botox will work by the morning.

Saturday, 8am

My forehead feels very heavy, as if there’s a slab of ice on it. This could be the effect of the alcohol.

Saturday, 10am

This must be how people live when they don’t have children. They wake up feeling dreadful, then they go back to sleep. I stumble into the bathroom and see for the first time that the Botox is starting to kick in. My forehead is almost wrinkle-free. But, rather worryingly, a new wrinkle has appeared, right at the top of my forehead. This one is obviously compensating for the fact that the others have been ironed out. Hopefully, it will vanish in time.

Saturday, midday

I am spending most of the day in front of the mirror, monitoring my forehead. It still feels heavy, but it looks a lot better.

Sunday, 9am

Eureka. The wrinkle has gone. Well, almost. It is a shadow of its former self. And the crow’s-feet are slowly slipping away.

Monday, 8am

Am amazed at how far back I have to lean to get my mascara on. My eyelids seem to have doubled in size. This is slightly disconcerting: I am no longer in control of my face and its contents.

Monday, 10am

Am in the Channel Five News make-up room. “Can you look up, please?” asks the nice make-up artist.

“I’m afraid that won’t be possible,” I reply.

Monday, midday

Call husband to ask what he thought of my television appearance. “It didn’t really seem like you,” he says. I decide that a phone call from London is not the time to break the news about my betrayal.

Tuesday, 10pm

Smiling seems a little trickier than it used to be. The upside is that, when I do manage to smile, the crow’s-feet are minimal, so when I smile, I look younger, not older.

Wednesday, midday

Exactly a week later, I decide to see Brenda about the new wrinkle. She says we’ll get that one next time.

Thursday, 8pm

Am at home. My husband hasn’t noticed a thing. Should I tell him? Probably best to wait until the morning.

Friday, 8am

Looking at my face for the first time properly, in daylight, in my own mirror, I see that I really do have fewer wrinkles. The worrying thing now is that I can’t see how I’ll ever live without this. I quickly call a friend for advice while Rupert is watering the garden. “Should I tell him?” I ask.

“What’s the point?” she replies, but is more interested in the results of the Botox than my marriage. “Does it really look better? I can’t wait to see you. Can I come next time?”

My husband brings me a glass of orange juice. “It’s lovely to have you home,” he says, hugging me.

I wait for him to add: “And you look incredible, at least 10 years younger. London obviously agrees with you,” so that I can confess. But he doesn’t, so I don’t. I keep quiet. I feel like a traitor – a wrinkle-free traitor.

Two weeks later, in a bar

A romantic dinner may seem an unlikely place to confess to my husband, but I get drunk. There is a slight misunderstanding on the number of caipirinhas we order, and I end up drinking two, which sends me over the edge.

I am extremely nervous, but the alcohol is making me brave. I tell Rupert what I did. He almost falls off his chair, but that could be the cocktails.

“You mean, you went ahead and did it?” he asks. “Even when you said you wouldn’t? That’s just plain dishonest.”

I wonder if crying might be the best strategy here, but instead opt for total surrender. “I’m so sorry, but I knew you’d stop me and it was one of the things I had to try.”

“You’re going to turn into one of those mad women we used to laugh at, aren’t you?”

“No, of course not.” “You say that now, but what’s next? Surgery?” “Never,” I say, as solemnly as my alcohol level will allow. “No scalpels, I swear.”

“It is odd,” he carries on, “but when I saw you on TV, I asked myself, ‘Who is this woman I’m married to?’ It was a horrible feeling. I just didn’t recognise you.”

“And now?”

“Now, you seem to be back to yourself. But you’re right,” he says, peering at my forehead. “You do have fewer wrinkles.”

I smile. “Look, no crow’s-feet,” I crow. “Anyway, do you like the new, Botoxed me?”

“Yes, but the problem is, I can’t see when you’re ever going to stop.”

“Oh, no,” I protest. “This was a one-off.”

I know I’m lying, though, and when I next see Botox Brenda, I’ll jump back on her couch quicker than you can say, make mine a caipirinha or two.

To Hell in High Heels by Helena Frith Powell (Arrow Books £7.99) is available from Thursday. To order for the special price of £7.59 (inc p&p), call The Sunday Times BooksFirst on 0870 165 8585 or visit www.timesonline.co.uk/booksfirst