A single white spot on your baby's cheek is very common and usually harmless. In winter, this is often just dry, chapped skin or a mild, temporary loss of pigment from drool or dry air (sometimes called pityriasis alba). To treat it safely, apply a thin layer of plain, fragrance-free petroleum jelly or a gentle, hypoallergenic baby moisturiser to protect the skin. Avoid using any medicated or steroid creams without a paediatrician's guidance. Please have your paediatrician examine the spot if it spreads, becomes red, flaky, or seems to cause your baby any discomfort.