My baby11mo. has redness around her belly button only, it's a week now.. what could this be? can i put anything on it?

Inflammation: Redness around the belly button is much more common in newborns than at 11 months. Earlier it would certainly be a local infection and potentially quite serious. At this age, a bug bite, with a local reaction is more likely. Some warm most packs would be useful. Then put on a topical antibiotic salve (neosporin) or better still calendula ointment.