How to sleep while in severe pain?

At the moment of writing this, I have been awake for just over 70 hours now, and I really need to sleep.

The problem is I have a bad tooth. I have been to the doctor, and have been given pain killers, antibiotics and some other medication.

However, I have been taking the medication for almost 3 days now, and I am still not able to stop the pain unless I keep my mouth full of cold water.

The nerve in the tooth has started to die, and it feels like I am being stabbed in the face unless I keep my mouth full of cool water.

I have instructions from the doctor to take the medicine, then go to an appointment that has been set with my dentist. All I need is something that will help me get some sleep for now.

Any ideas?