Baby bites during breastfeeding 😬

Please help! Anyone experienced their child biting whilst nursing? My son is 15 months and been breastfed since birth. His biting hurts so much that I’m in agony! He leaves bite marks and tried telling him not to do that. I do want to eventually stop breastfeeding as it’s getting hard for us both now. He will bite more when he’s teething and he seems frustrated when flow of milk isn’t as much