Oh gosh, i remember that!! so painful!
I would stop breastfeeding and told baby not to bite and if he still continues. I will stop completely, wait 30min then resume.
Even if baby laughs, you're doing the right thing by stopping the feeding and firmly telling her “no” when she bites. Wait at least 30 minutes to start back up or end the nursing session completely, so baby gets the message that biting doesn't get rewarded with food.