Hi. My Boyfriend Has A Broken Tooth. Well The Tooth

Hi. My boyfriend has a broken tooth. Well the tooth is gone it fell out months ago, but a small piece of the tooth at the root remained inside. It was the first little molar towards the front on his bottom left. Now suddenly the gums underneath the gap of the missing tooth is swelling, on the inside of his mouth it looks like a ball/bubble has formed (maybe of pus?) And is getting larger quickly. The left side of his face is swelling and increasing quickly. So much that it looks like he got hit. He's in a lot of pain. He has been gurgling salt water, taking tylenol, attempted to apply ambesol, nothing seems to be helping treat his pain or swelling until we can get to the dentist on Monday. We have no antibiotics. It's getting worse. He feels like it's going to pop inside. What can we do?