My 13 year old daughter showed me a couple of red bumps on her legs a couple of days ago. One had Gone away and left a white circle in its place, almost as big as a dime. She said it had scabbed first. Today she showed me her lower buttocks, where they meet the top of the leg, have several large scabs, some as big as a quarter. It almost looks like she sat in something. I plan to take her to urgent care in the morning, but what could this be?