brush with salt water and baking soda, put a dab of hydrogen peroxide on it and rinse out. it will hurt like heck but do it anyway, it will feel much much better within 10-20 minutes.

probably just a coincidence. if your face is swollen there is definitely an abcess in the tooth and your dentist is going to tell you need a root canal which you should forego in favor of losing the tooth. unless of course the idea and expense of a root canal doesn't bother you (research it) but you'll probably only lose the tooth within 5 years or less anyway. root canals never really cure an abcessed tooth.

I'd dab some clove oil on it too after the h2o2. swish clove oil around your entire mouth. Goldenseal root is a very effective anti-bacterial also. You can swallow that.

good luck.