My 13 Year Old Started Complaining Of A Raised Ulcerated

my 13 year old started complaining of a raised ulcerated area on her heel that was painful and became pussy. I have cleaned this area up, but it is still raised and bumpy and looks like there is something underneath it. Now, some ulcerated bumps have just appeared on her buttock. There is a cluster of 3, that look like small blisters in a circle. Any idea what this may be and how to treat?