It's the pits.

My armpits are always black. I scrub so hard that they turn red. I shave, but it's not hair. Help.

Save the scrubbing'--it won't help. A few things can cause darkening, explains New York City dermatologist Dr. Ariel Ostad: 1) You could genetically have extra pigmentation there. 2) You might have a condition called acanthosis nigricans, which has to do with high insulin levels. If you're also dark around your neck, waistline, knuckles or elbows, see a doc. 3) You might have a buildup of dry skin thanks to antiperspirants and shaving. Try a lotion with lactic acid (try AmLactin 12% Moisturizing Lotion) in your pits at night. If you see no improvement after six weeks, see a doc for a bleaching cream or to check insulin levels. You'll have peachy pits in no time!

I get nasty bumps around my panties. They look like pimples, but I'm scared it's herpes!

If you aren't sexually active, it's unlikely you have herpes. They're probably zits or ingrown hairs--the genital area has tons of hair follicles and oil glands. Don't pop or pick--ouch, ouch! Acne creams are too strong, so just wear loose-fitting panties to let the skin heal, suggests Dr. Marjorie Greenfield, associate professor, pediatric and adolescent gynecology, University Hospitals of Cleveland. To offset future bumps, soak before shaving. Use cream and a fresh razor, and shave in the direction the hair grows. If outbreaks continue, see a doc.

I bite the insides of my cheeks, especially when I'm stressed out. Any ideas on how to stop?

Many girls have this habit. Time to talk to a trusted adult or school counselor to ease your anxiety in a healthy way, explains Dr. Susan S. Bartell, a New York City psychologist. Once you've gotten to the root of your stress, you can nix the cheek-chomping. If you just can't stop, ask to see a therapist.

I get this itching between my legs at night, and I end up scratching a lot. What gives?

Sounds like a classic yeast infection. Yeast are microorganisms that naturally live down there. When the yeast overgrow (antibiotics, wet bathing suits and tight clothes can cause this), they irritate vaginal skin. You shouldn't notice a weird odor (that's another treatable infection), but you will itch like a baboon. Even though there are over-the-counter remedies, see a doc for a diagnosis, especially the first time you have one of these pesky infections.

FACT OR FICTION?

Diet soda can make you fat

FACT! A study at University of Texas Health Science Center, San Antonio, showed the more diet soda people drank, the more overweight they became within an eight-year span. The theory is that artificial sweeteners boost appetite. Also, drinking diet gives you the sense that you've saved calories so you can fill up on other high-calorie junk food. So instead of reaching for a diet soda, gulp water, flavored seltzer or unsweetened tea.