Suggest Treatment For Bumps On Armpit With Rashes On Face And Back

My 11 year old daughter has noticed some bumps under her armpit(only on one side) that hurt when touched. She also has a rash on her face and a few pimple like bumps on her face as well. She has also noticed the same type of bumps on her back and a few on her legs. I was wondering if you could possibly tell me what it is? My son also has a couple on him, one on his thigh he says hurts.