I have a cavity in a wisdom tooth and I believe it has absessed, how can I treat pain until I can get to dentist. Am in lots of pain and pain is growing.

You . You need to see a dentist asap to take care of your problem before it turns into a severe emergency. Obviously taking otc pain meds will help, but not solve your problem.
Request antibiotic. If your wisdom tooth is decayed and abcessed, you will need to see your dentist right away. Do not wait. Meanwhile, you can request some antibiotic and anti-inflammatory drugs for relief.