My bathroom remodeling completed, I was looking forward to preening in front of my new mirror and state-of-the-art vanity lights. So you can imagine my horror when I noticed that the delicate veining of the recently installed Carrara marble tiles was almost a perfect match for the ropey white lines running across the surface of my butt. Surprise! I had stretch marks.

Typically associated with pregnancy, adolescent growth spurts, breast implants, or bodybuilding, stretch marks are caused by a surge in hormones and an overextension of the connective tissue under the skin. But I'd actually shrunk recently — losing only five pounds, but enough, according to Los Angeles dermatologist Dr. Ava Shamban, to highlight lines lurking beneath the surface. "If you have a genetic disposition, you'll probably get them," she says.

Technically, these aren't my first — I've come to terms with the striations on my lower back from a three-inch sprouting in seventh grade. But somehow the lines on more intimate zones like the bottom or upper thighs are, well, horrific. A butt that resembles a bowl of coleslaw, smack at the start of beach season? And forget trying to "tan" your stretch marks, adds Shamban. The flawed texture of this area doesn't darken like normal skin — whether you're sunbathing or self-bronzing.

So I start stockpiling any product that even mentions stretch marks. Shamban suggests experimenting with scar creams, retinols, and peptides. "Anything that repairs collagen will make the area look smoother," she says. After glopping on numerous potions, I learn that my skin responds best to gels. They penetrate the fastest and tighten the skin. But who am I kidding? I'm lucky if I get around to applying body lotion more than once a week; fat chance I'll massage a special tonic on my bum twice a day. Advice from a friend — who hasn't worn a bikini since she was 22 because she's so self-conscious about the lines on her lower back and belly — is less than encouraging: "Give up," she says. "I hate mine — I think they make me look like I've had three kids when I'm only 28 and single — but none of the creams I've tried have helped." Clearly, topicals aren't enough.

Besides, over-the-counter options only promise to "improve the appearance of stretch marks." How about getting rid of them completely? Even lasers, which have been around a few years, don't seem to work for everyone. They're most effective on fresh marks, so anything past the preliminary pink stage is basically beyond them. Real removal requires two types of lasers alternated over a series of treatments, says Beverly Hills dermatologist Dr. Harold Lancer. "One to get rid of the redness and another to eliminate the torn look," he tells me over the phone. Hmm ... I'd never seen any redness — so maybe mine aren't stretch marks at all! Maybe I just need to exfoliate more?

Optimistically, I scrub myself down, which renders my white marks an alarming pink. Needing a second opinion, I schedule a consultation with Dr. Macrene Alexiades-Armenakas, assistant clinical professor of dermatology at Yale University School of Medicine. "Stretch marks aren't actually white at all," says Alexiades-Armenakas, who made this discovery recently. "The lightness is an optical illusion. Collagen is typically crosshatched, but stretch marks' collagen only goes in one direction, like scars. They reflect light and change color at different angles — appearing white, pink, red, or darker, depending on your skin tone."

I hold my breath and pull down my pants so Alexiades-Armenakas can give me her diagnosis. "Those are definitely stretch marks." Darn. "Sometimes you never notice the pink phase because it can blend into your skin." She recommends Alma Lasers' new AccentXL system, which uses radio frequency to heat up the deeper layers of the skin and encourage healthy, cross-linked collagen production. It's not cheap: The AccentXL treatment is a hefty $600 to $1000 per visit, and a full regimen usually requires four to six weekly sessions. (A similar device, in effectiveness and cost, is Thermage's ThermaTip CL.) Still, I'm told the results are long-lasting and will not only erase my stretch marks but also zap cellulite and firm the entire tush and upper-thigh area. Sign me up!

Because AccentXL doesn't burn to achieve its results, my treatments are pretty much painless. First, Alexiades-Armenakas's assistant applies baby oil to help the laser glide better. For the next half hour, I feel like I'm getting a hot-stone massage at a spa — though I'm in a rather sterile treatment room, wearing a blue paper gown under bright lights. My whole butt looks flushed after the procedure but returns to normal after another 30 minutes. It takes a while for the body to produce collagen, so I'm told not to expect immediate results. Nonetheless, I swear that two nights after my initial treatment, when I emerge from my hot bath, my bottom has the nice plump appearance of a baby's. And after I apply Bio-Oil (the scar reducer), my stretch marks are nearly invisible. Three visits later, they're almost completely gone (even without oiling up) and — bonus points! — I'm fitting into the superskinny jeans I haven't been able to wear for two years. Meanwhile, back in my spanking-new bathroom, I observe that my "new" behind is at its personal best (10 years younger, I'd estimate) following a long soak in my whirlpool tub. "After a hot shower or bath, the skin swells and looks temporarily smoother and free of any superficial lines," Alexiades-Armenakas confirms. Note to self: Before slipping into a swimsuit, take a dip in the Jacuzzi first.

Here, the best products for treating stretch marks and cellulite

What Do You Think?