If the bun is sneezing a lot, then you might wantto check for any other signs, bunching up like he is in pain, dischargefrom the nose or eyes, matted paws from wiping a sniffly nose...
if there are no other signs, he could have just gotten into a patch of dust or something. Or have allergies.
If you want to play it safe before you go off to school, take him to the vet and get a checkup =) it never hurts!