It is completely normal and even cute for your puppy to nip at your hand a little. Since your puppy has only been exposed to other puppies in the litter, his only way of playing is with his mouth. So he assumes that playing with them would be no different. Here are some tips to teach your puppy to stop biting.
1. First take a small treat in your hand and enclose your fingers so he doesn't have it. You have to wait for him to move his nose away from your hand. He needs to know that he's never going to get the reward by picking at your hand.
2. It is important to teach your dog how to play with toys instead of your hand. Play is a healthy natural activity that helps build a bond between you and your puppy. Before you teach your puppy not to bite it is important to teach him how to reduce the pressure of biting.
3. Use an inexpensive dog training collar to reinforce good behavior.