puppy aggression

[lottie6980]

Hi all,
I have recently got a 5 week old puppy who is constantly biting, I have tried every 'stop biting' technique I can find and nothing is working, when I tell him no he growls and comes back again to bite me, he does this time and time again, I have a 9 month old baby and can't help but worry that he will not lose this aggressiveness, please help!
I have also tried shouting ouch! And walking away this worked at first but then even though I'm shouting ouch he doesn't let go of my hand and I sometimes have to open his jaw to release my hand.