My 3 year old has been getting red itchy painful pimples on her buttocks that scar as they heal. They are now spreading to her upper thigh and back, and her 5 year old sister is getting them as well. Very random places and isolated, not groups. The pimples seem to dry up and heal within a couple of days, but then others appear in unrelated places. I,ve taken the toddler to the GP, he thought diaper related, but I don't think so now, as they seem to spread.