P.T.
Oh my gosh, my daugther went through the same thing. She was bit by another kid during playtime and at the babysitter's, one of the other kids leaned over and bit her on the lip out of jealousy. She then thought this was a normal thing to do and started biting other kids. Some times out of frustration she would bite her own hands. I bought the fisher price plastic stacking donuts that comes in colors. I took one of them and tied a long string ti dangle the donut. I also took the doughnut to school. Whenever she was caught biting or trying to bite, the teachers worked with me and had her sit in timeout biting on the doughnut. It took 2 months and stopped biting.