My Gidget was a biter at 14 weeks old, but never so hard that it drew blood. I used a very loud OUCH (shrill) and I just continued doing that every time she even looked like she was about to bite me!
I have to say that now she is just the gentlest little thing ever. A total love bug - never bites, just kisses. So I would say, hang in there. Ignoring him after the shrill OUCH is a good idea.
Good luck.