How likely is a brain abcess from a bad tooth?going to dentist monday.on zithromax, penacillin allergy.im a migrainer so i have migraine and sore neck

Not very unless: Unless it is an upper tooth with a long term abscess. It typically would take a while for a dental abscess to enlarge enough to cause a brain abscess. Possibly you have a concurrent medical problem that is causing your sore neck. Talk to your physician. Your dentist needs to definitively treat your tooth problem (extraction or root canal treatment).

Not likely: Most dental infections remain localized around the tooth. Left untreated they may progress into a localized abscess or cellulitis. Only sometimes will it become systemic. A person may develop a fever, especially if they're immunocompromised. If you develop a fever, difficulty breathing, or facial swelling, seek immediate care. Despite this, spreading to the brain is not common. Best of luck!