Thank you for the opportunity to respond to your question.
I sympathize with you. I know how uncomfortable this must be.
If you have been to the dentist and this is a sequel to treatment you received at the dentist office, then I recommend that you use Ice Packs to help reduce the swelling. I also recommend that you take aspirin according to the instructions on the bottle. If you are allergic to aspirin, you can use motrin or tyleno..... The drug of choice here is Aspirin.
If this is a spontaneous event and you have not been to the dentist , what you probably need is an I&D of the tooth, because of what I suspect is an abscessed. The infection could possibly spread to your jaw and face, or is compressing vasculature to cause flood to build up in your face.
Since you cannot I&D your own tooth you can do the next best thing for now. Brush and Floss your teeth. Make sure you floss the bad tooth very well. You may notice a strong taste and some stuff come out out. This is OK. Rinse your mouth well with Listerine mouth wash.
Call the dentist for an emergency dental call in the morning.