Your puppy biting is somewhat normal, although not very exceptable, and can be stopped. I have had the pleasure of raising 12 dogs, all of who live with me now. I have had this problem with at least 10 of them. What I do is this, if the puppy starts to bite, I deepen my voice and simply say, "No, don't bite." Most times this works, if not I ever so gently tap quickly once or twice with the pad of my finger on the bridge of the pups nose and say again, "No, don't bite." Never hit or yell loudly at your dog. And when I say gently tap, I mean very gently. This method has worked every time for me, and does not traumatize the puppy one bit.