C.R.
I don't know from a pediatric perspective, but somebody I knew as an adult had similar sounding spots and they were a fungus, not serious, but treatable with cream. I agree with the person who posted that it was strange for the doctor to start treating it with ointment when they didn't have any idea what it was, but that is what doctors seem to always do, at least in my experience with my 5-year-old. They pass out drug samples like candy.