Toddler being bit at daycare

I just got a call from daycare and they said my 17 month old DD got bit on the face today while playing with another kid. They said it did not break the skin but left a mark. This is the third time in the month of October she has been bit. None of them have broken the skin but they were definitely hard bites and each left a bruise for over a week (the last one, from last week, is still bruised!) ... I plan on having a talk with the center's director today but I guess I'm wondering what all I should ask?  Any insight? Here is what I have come up with so far:

What do you do immediately when a child bites?
Is it the same child biting, or different children? (The first two bites were from different children)
Is the biter separated from the child that was bit, and/or from the other children? And for how long?
What do your teachers do to try to prevent biting or biting behaviors?
Does the parent of the child who bites also receive an incident report?

The recent biting aside, we really love this daycare. They have an excellent program and the teachers and director/assistant director all seem very caring and involved. They are certainly not the least expensive. But I'm debating shopping around, especially with a second LO on the way.

TIA for your insight ... I'm feeling really guilty right now.