How do i get my puppy to stop biting.

Hi! I got a German shepherd who’s just about 10 weeks old. Been with us for 2 weeks now. He keeps playfully biting and he doesn’t stop even when i yell ow, as stop or try to give him something else. It didn’t bother me too much until today. This morning, like 3 minutes ago, my mom was cleaning so I want to pick up his poop, in which he comes up to me and bit my finger so hard that it’s genuinely bleeding and hurting. Like, bad, i feel the blood pooling out. I don’t know what to do, I don’t want to rehome him but I’m worried if we can’t get him under control he might hurt someone else especially when he’s older.