You can't, as it is infection causing the swelling. Try calling your GP and tell them your situation and see if they will give you an script for antibiotics. The dentist won't touch it while it's abcessed, and would put you on antibiotics to clear up the infection before doing anything with the tooth. If you have a regular dentist, I would think they would also write the script, since this will be thier first step anyway.
You could do some warm salt water rinses - to help pull the infection out, use some oil of oregano as well. Mammo's right, you'll need to get a script to fight the infection before a dentist can do anything.
The Content on this Site is presented in a summary fashion, and is intended to be used for educational and entertainment purposes only. It is not intended to be and should not be interpreted as medical advice or a diagnosis of any health or fitness problem, condition or disease; or a recommendation for a specific test, doctor, care provider, procedure, treatment plan, product, or course of action. MedHelp is not a medical or healthcare provider and your use of this Site does not create a doctor / patient relationship. We disclaim all responsibility for the professional qualifications and licensing of, and services provided by, any physician or other health providers posting on or otherwise referred to on this Site and/or any Third Party Site. Never disregard the medical advice of your physician or health professional, or delay in seeking such advice, because of something you read on this Site. We offer this Site AS IS and without any warranties. By using this Site you agree to the following Terms and Conditions. If you think you may have a medical emergency, call your physician or 911 immediately.