Infected tooth removed 2 months ago lymph node under jaw still swollen ct scan negative no other symptoms what can this be?

Swollen node: Lymph nodes can remain swollen after an initial infection is gone/treated. Sometimes they can calcium deposits in the node making it remain firm/swollen-CT should have showed calcification. You should continue to monitor the size and for signs of warmth,redness, and pain. Follow up with your doctor or dentist if symptoms worsen.

Antibiotic: you should be treated with antibiotic and if no respond ,need biopsy