If your child was bitten hard enough to bruise some sort of reaction had to happen at the school when it happened (OW! hey don't bite me! something...). If that was not noticed or reported there is a HUGE problem. I am listed under a friend's daycare license and if a child is EVER hurt you have to write it up and inform the parents. Same with the daycare/preschool/K program Wolf goes to. If a bite that hard went unnoticed that means the teachers are not paying enough attention and that is DANGEROUS!!!
The fact that they are getting on your case about pulling him and not bending over backwards apologizing to cover their butts for missing that astounds me.
You did exactly the right this by pulling him and if I were in your shoes I would inform the principal of the bite incident and that it wasn't reported. Heck I'd send an email straight up the chain on that one.
