Prevent 'em: Make sure the sores do not touch the child's face -- so nix any kissing when you or someone else close to her has an outbreak. If you're the type who gets the telltale tingle right before a cold sore pops out, lips off then, too. You're contagious right before and during an outbreak, and a few days after a blister heals. It's also smart to avoid sharing cups and utensils, and to wash your hands frequently. And because it's hard to know if someone else gets cold sores, "ask other people to tickle and touch your baby's feet [or belly] rather than her face," says Dr. Altmann, especially when she's an infant.
Relieve 'em: If you suspect your child has a cold sore, take her to the doctor. The initial outbreak will likely be the most severe, sometimes with painful blisters inside and outside the mouth. Your doctor may recommend an over-the-counter topical medication to ease the pain and to keep the area outside the mouth moisturized, but usually Vaseline is all you need. You can also try a warm or cold compress to relieve discomfort. Sores last about a week, and there's no cure for the virus that causes them. Stress, illness, or even sun exposure may trigger them -- another reason to slather on the SPF.