May 24 issue - Perched on the edge of the examination table, I was chattering away to my dermatologist, Dr. Penny Lowenstein, as she examined my skin last December.

Uncharacteristically quiet, she pulled out a magnifier to peer at my face. "Feel anything strange above your lip?" she asked. My heart sank. Squeezing my eyes shut, I whispered, "No." My palms started to sweat when she said, "Precancerous." It was actinic keratosis, and the treatment wasn't pretty. I had to smear chemotherapy cream over the dime-size spot for the next 12 days—destroying the diseased skin, but turning it into a mass of angry red pustules along the way.

I've been through this skin-cancer thing before. A few years ago I had a basal-cell tumor. Known as "the cancer to get if you've got to have cancer," it's slow growing and it rarely spreads. That was the good news. The bad news was that it was on my forehead. Vanity took flight when I learned that, untreated, it would worm its way into my brain. A plastic surgeon dug it out, leaving me with a perpetually uplifted eyebrow.

I knew that early sunburns trigger skin cancer. When I was a kid, no one used sunscreen. I blistered from burns every summer; no one ever thought twice about it. As a teenager, I slathered myself in baby oil and roasted myself red as soon as the weather warmed. But the only concession I made after my basal-cell diagnosis was to cover my face as I sunbathed in secret. And to go for my yearly skin check.

The next year I was in for a shock. Suspicious spots were cut out and sent to a lab; a few days later I learned that I'd sprouted a dysplastic nevus—a mole that might morph into melanoma—on myneck, a squamous-cell cancer on my collarbone and a melanoma on my shoulder.

Squamous-cell carcinoma is several notches higher than basal on the Scary Cancer Scale. It grows more quickly and more deeply, and pieces can break off and lodge in inconvenient places like your lungs or liver. It seemed impossible that the skin tag on my collarbone, a teeny little bump, could have turned so monstrous.

Melanoma is the most menacing of the skin cancers. Masquerading as a freckle, it can wreak havoc without any symptoms. If it's not caught early, major organs can become riddled with the disease. It's a cancer that usually strikes people in the prime of their lives, and the five-year advanced-melanoma survival rate is grim.

Which is why I was distressed at this latest development. After umpteen precancerous moles, heaps of biopsies and four skin cancers, I scrutinize my skin like a zealot, poring over my pores, inspecting my insteps and even looking "down there." I figured that between my own vigilance and the now quarterly dermatologist visits, I was covered. I was even blase.

But when Dr. Lowenstein handed me a mirror and shone a bright light onto my face, I could barely make out three scaly spots. What I thought was a touch of dry skin was actually a time bomb.

When I told my husband, he blanched. "I can't believe it. Come into the light and let me look." Little did I know that he, too, analyzes my skin relentlessly. "So if you weren't doing these skin checks, this little thing could have killed you?"

Yup. It shook me out of my complacency. Searching the Internet for information on actinic keratosis, I found page after page on skin cancer. And I remembered how disfiguring the treatment for basal- and squamous-cell cancer was—I have enough surgery scars to call myself the Bride of Frankenstein.

Then I stumbled across the Melanoma Patients' Information Page. The "guest book" is chilling. A pregnant mom's 38-year-old husband has end-stage melanoma. A woman with three young children agonizes over two nasty therapies. Someone else writes about her own mom, 58—diagnosed in April, dead the following March.

Though teens obsessed with tanning beds have become enough of a trend to be dubbed "tanorexics," many more kids avoid skin cancer now because of prevention efforts. What about the rest of us? We know we should stay out of the sun—and I've kicked my sunbathing habit—but what about all the years we didn't? The damage is done, but we can do something about it.

Got an irregular-shaped brownish-blackish spot, or what looks like a zit but lingers and bleeds, or an itchy bump that seems a bit bigger this month? Call a skin specialist, and have yourself checked from head to toe. Catch a cancer early and you might avoid mutilating operations, brutal treatments and early death.

Not quite five years after my melanoma, I'm alive today thanks to skin self-checks and an astute dermatologist. Smaller than a pencil eraser, that freckle wanna-be could have erased my whole life.