While you're smart to slick on lip balm during the day, it's also important to pamper your pucker at night, says Heidi A. Waldorf, M.D., an associate clinical professor of dermatology at The Mout Sinai School of Medicine in New York. Dr. Waldorf is also director of Laser and Cosmetic Dermatology at Mount Sinai Medical Center and has a private practice in Nanuet, New York.
At bedtime: Lips can chap severely while you sleep, especially if a stuffy nose forces you to breathe through your mouth. Apply plain petroleum jelly or a thick ointment containing mineral oil or glycerin. These ingredients seal in lips' natural moisture even when you aren't able to reapply often. (Good product choices include Bag Balm and Aquaphor, both available at drugstores.)
For daytime wear: It's fine to use a lighter lip balm or moisturizing lipstick. But you might want to avoid flavored formulas, which can induce you to lick your lips unknowingly and exacerbate chapping. Also, lip balms that contain a high concentration of menthol or camphor -- often touted for their "cooling" properties -- can irritate severely chapped lips. If chapping persists, see a dermatologist to rule out a more serious skin condition such as yeast overgrowth.