Swollen and hot to the touch mark on a child, what's wrong?

Swollen mark: A mark on a child, particularly a red mark, that is swollen and hot, could be an indication of a skin infection known as cellulitis. Another sign would be pain when the "mark" is touched. This could require antibiotic therapy, especially if you notice the mark growing in size. If that is the case, it should be examined by your doctor.