Breaking through the skin and clothing sounds especially vicious and could be medically hazardous (and if it gets infected and you are stuck with medical bills, the day care can be held liable). You are right to be concerned and suspicious about what is going on when you are not there.
I recall the day when I got TWO accident reports in one day for my son, who was bit on one thumb by one kid and then on the other thumb by another! I was so upset...
One bite can be expected. More than one signals a lack of appropriate supervision and/or discipline methods to address the issue. I am concerned that this day care is not doing enough to curb the biting.
I believe that a 6 to 1 ratio of children to teacher is OK after 18 months of age but I would confirm this online through your state's website on child care regulations.
Also, it is a legal violation of personal privacy to reveal the name of the biter. The concern is that some crazy parent might try to confront the biter's parent in some way that may be violent, and the day care does not want to be held responsible. However, the day care does reserve the right to kick out any child who is a repeat biter -- so, when they talk to the parents of the biter, they should be discussing this with them.
I would keep your appointment talk to your director in person about what is going on, and avoid the phone. In person always carries more weight than a phone call. I would also specifically plan on asking EXACTLY what was done to handle your daughter's biting situation -- and listen carefully: a good director, if she examined the situations over and over with a fine-toothed comb, should be able to explain the situations easily and vividly. If the director struggles to remember, then that means that she was not really on top of the matter as she claims she is being.
Other questions you may want to ask are:
-Which teachers were present those times that your kid was bit? Did the director talk to the teachers and what did she say to them? What did they say to her? If it was the same teachers, is that of concern to the director (in other words, could it be that 1-2 teachers in particular are not as watchful as they could be)?
-What was said to the biter by the teacher? What was done (ie methods of discipline)?
-Is there a plan on how the biter's parents will address the issue of biting (the day care is obliged to suggest to the parents how to address the issue at home to avoid it happening again)? Is there a threshold on how many "bites" or similar behavior it would take prior to expelling a child from day care (and I would hope that the director has a very specific answer for this)?
-Overall, how has situations like this been handled in the past?
-Is there lots of biting at the day care in general (the answer should be no)?