Bit at daycare

So I have the privilege to work at the daycare my son attendeds. My son is 1.5 years old. I happened to walk past his classroom and saw his teachers hold him as he’s sobbing and real tears down his face. Mom mode kicks in and I go in to see what’s wrong with my son. They proceed to tell me he was bitten. Now my son isn’t any angel and is a biter himself but what would your reaction to this be?? (Photo a few hours later in the tub)