I have been on antibiotics on and off for a month for severe tooth decay and abcesses. what are the chances of it spreading to my neck while on antibiotics?

Oral infections: Mantibiotics lone will not cure abcessed teeth. You need to treat these teeth or the infection will return. And the bacteria can become more resistant to antibiotics. An out of control oral infection can progress down the neck and cause serious problems. If you are having difficulty breathing or swallowing this is an emergency situation and you need immediate treatment.

Possible: It's possible for the infection to turn chronic and spreads to other surrounding vital areas , take care of the problem (the tooth) followed by proper antibiotic treatment would be best..

Won't work: Antibiotics do not cure tooth infection. You have to see dentist/endodontist/oral surgeon for root canal rx or extraction. Antibiotics may prevent spread of infection to other tissues, but as you have experienced from long term antibiotic treatment, pills will not cure an abscess nor will it cure infected tooth material (decay).

Need dentist: Without seeing a dentist, the antibiotics may only treat some of the symptoms, but not the source. The infection can easily spread into the blood stream and elsewhere. Get to the dentist asap.

It is possible: Antibiotics can start providing relief anywhere from 24 to 72 hours. If you don't have any relief by 72 hours you should call your dentist as you might need a different antibiotic or an emergency dental treatment. For temporary relief you can take OTC NSAIDs or Tylenol (acetaminophen). The only way to cure a dental infection is with dental treatment.