I am going for a tooth extraction tomorrow and I am allergic to penicillin and antibiotics. What should I do? I am in a lot of pain.

Antibiotic allergy. I am sure that there is at elast one antibiotic that you are not allergic to. Worthwhile to be evaluated by an allergist to see what you are truly allergic to. About 80% of patients who walk in claiming to be allergic to penicillin are found to be not allergic!
Alternative. There are always alternative antibiotics. You just need to ask the surgeon which alternatives are available. A simple phone call is all it takes. Then get into an allergist to truly determine if you are allergic to certain antibiotics. We do have excellent testing for this.
Do you need it? Antibiotics are prescribed to treat an infection or to minimize the risk in an individual with a predisposing condition requiring prophylactic coverage. Pain by itself would not be an absolute indication that you require antibiotic therapy. Your dentist or surgeon will evaluate your condition and prescribe the appropriate antibiotic if indicated.
Pain Treatment. There are numerous available antibiotics and usually an alternative can be found if someone is allergic to a specific class of antiobiotics. The provider who pulls your teeth should have training in following up with you after the procedure.