My son was bit at daycare

My son is 19 months old, when my mom brought him home from daycare today she saw he had a bite mark on both arms and his face! No employees/teachers said anything to her about them when she picked him up. We called the daycare director who said yes a slightly older boy (2ish) bit him today but they put ice on the bite marks. She said something along the lines of they're at that age where biting is a phase.

My son is not a small 19 month old so this boy had to of been holding on to him (its not like he held still to be bit 3 times). I'm bothered that no one told me (they have my work nunber) or my mom when she picked him up. And how did he get the chance to bite him 3 times before someone stepped in?!

I'm sure my son has "moved on" and forgotten about it but I'm so heart broken and mad for my baby :(