My advice is to go the hospital emergency department today, because I'm not certain your dentist has done the right thing. Surely an abscess involving the jaw and a tooth is more serious than just going home and taking antibiotics? I've never had one but I've heard a few stories of people having them, and they always seemed to get a tooth taken out, or minor surgery done to drain the abscess. I have had an abscess elsewhere on the body and it was very painful, with a high fever, and I needed surgery to drain it.
It sounds really painful for you. A doctor might give you strong pain meds, or even admit you to hospital for IV antibiotics and other treatment. I think at the very least a second opinion from a dentist is needed, and seeing a doctor might be even better. You could have quite a fever. I hope you get some help asap.
In the meantime, holding some ice cubes in a bag on the side of your face might ease the pain and swelling. Drinking pureed food through a straw might be possible? Small spoonfuls of scrambled egg?