What is on my child's leg?

Lala♈ • Drinkin' outta cups, bein' a bitch.

This popped up on my 5 year old almost a month ago. It wasn't bothering her so I just put some hydrocortisone on it every night and it started to go away. Now it's back and it's getting red and irritated, she still says it doesn't hurt or itch. She has a dr appt on the 2nd. I'll have it looked at then but I'm just wondering if anyone else has seen this?