Your newborn may already have a blister over the upper lip or on the hand from sucking in utero. Small white cysts may also appear on the roof of the mouth; they're harmless. Some babies have soft milk teeth that usually fall out. You may also notice thrush; that's a common yeast infection on the insides of baby's cheeks, gums, or tongue. Thrush looks a bit like cottage cheese, and if wiped at, it may bleed. A doctor can treat it with medicine, but it rarely hurts or bothers baby—although your breasts may get sore with it if you are nursing. In that case, you and the baby will need to be treated.