I agree, this sounds like more than puppy play. She has to be shown that biting is never accepted. If she plays too hard, you just stop playing after you tell her NO. But it sounds like she is being aggressive other times also. Even a small dog can give a bad bite; you must train her not to do this. Putting her on her back and forcing her to submit is one good way to help her. If you can't train her yourself, you will have to get professional help. Sometimes dogs bite out of fear instead of aggression. Watch the times she shows aggression and see if maybe it is fear, that is still not acceptible, but you may have to handle it less firmly ,but by helping her feel secure. Good luck, I hope this all works out fine.
