As someone said earlier -- don't take an antibiotic unless you take a FULL course. Not every antibiotic is appropriate for every infection. Generally oral abscess is treated with amoxicillin or related I think, unless you are allergic to penicillin.
Be sure you dissolve the salt completely before using the salt water rinses or you can trigger sensitivity in the tooth. Correctly proportioned salt water should not burn.
Peroxide used often will eat the insides of your mouth. At least mix it 50:50 with water. Same with listerine. use them only once or twice daily.
Even if you need dental care you can often treat the infection -- but you WILL need medical care to get an antibiotic.
Treating the infection may buy you some time even a few times, but as said earlier too, you can get blood poisoning if you let any infection go too long. If you have any fever or chills -- get to the doctor right away -- don't wait!