According the folks at the Dove Dental Center (from whose site I cribbed this text):
A dental abscess can cause pain in the face (usually from an upper tooth), or pain in the area of the lower jaw (mandible) - (usually from a lower tooth), due to a build up of pressure from an infection which is emanating from the pulp chamber of the tooth, causing pressure along tissue planes. The pain can be quite severe. You should seek advice from a dentist urgently to get the abscess drained. It may be possible to drain the pus through the tooth itself so the tooth can be saved (root canal treatment). If not, the tooth will need to be extracted to prevent the abscess from recurring.There is nothing quite like the pain of a tooth abscess--it is constant, throbbing, and eventually involves the entire head. Sleep is impossible without serious narcotics (Vicodin is my palliative of choice). It is the worst pain I have ever experienced, not having gone through childbirth nor passed any kidney stones.
Luckily, although I don't have dental insurance, I do have money, so I could afford to get my tooth treated and avoid death. The pain is better, although not completely gone, but I still don't have much of an appetite and a do have a fold drainage in my mouth (from the opening left in my tooth). I am mid-root canal, awaiting subsidence of infection and inflammation in my tissues before the tooth can be closed up again.
My dentist had closed the tooth with a soft plug after initially draining it; this caused a second night of excruciating pain and heavy narcotic use before he pulled the plug out. I am now recovering, and hope to return to blogging and other normal activities soon.