could be your son is allergic to the adhesives on the band-aid. it should go away in a couple of days. if not. wait. wait. go see the doctor. <positive_smiley> i would check with the school and find out what kind of band-aid so your doctor can have something to work with in his/hers diagnosis. not much you did not know but i hope your son feels better.
my son got a scrape on his elbow. there appears to be a rash where the bandage was. could this be an allergic reaction? . at first they were just bumps but now they appear white almost puss like. i do not know what type of bandage was used since this happened at school.