C.N.
That sounds like ringworm, which is actuallty a skin fungus. It's pretty common in the environment. There are OTC antifungals that will usually do the trick, but if they don't, your pediatrician can presecribe something stronger.
Be sure to wash your hands carefuly after treating the sores, becuse it is highly contagious.
If she's in day care or school, or in a situation where her clothes need to be changed during the day, you need to let them know.