Yea, lots of people do this. Glad to see you learned why you shouldn't though. What's done is done, so now you just make the best of your pup. I would just keep researching, because there's going to be a few things you will have to do extra hard. Mainly bite inhibition, and socialization. Your pup missed out on a very crucial learning period with his littermates and mother. If it's not something that is taken care of, you may have big problems down the road. So get yourself very, very familiar with these 2 topics.
Another thing, your pup is far too young to be out and about. You're going to want to wait a few weeks until all of his shots are done. Park should be a big no no, at this age your dog doesn't have a strong immune system and can get something and get very sick, or worse, die. So best to just stick around the house for a few more weeks until all of the shots are finished up. Do you know what has been done by the greeder in terms of vet checks, shots, etc?
I would also like to echo Adara, she is totally right. This is normal behavior for a puppy. He has zero concept of right or wrong, he just wants to do what he wants to do. If he hasn't been taught it's not ok, and shown an exceptable alternative, it's not wrong in his eyes.
Your going to want to be gentle, no muzzle grabbing. When he bites, let out a big scream, and make like it really hurt. Pretend he bit a finger or toe off... He will likely get freaked out. He needs to learn that his teeth are weapons, and they should not be used on humans. Try it a few times, see how that works. Act like he bit your finger off, let out a yelp, walk away, ignore him for a few.