The most obvious sign of a dental abscess is pain. It is usually severe and persistent, and may feel like a throbbing, gnawing, sharp or shooting pain. The pain of an abscess may be especially bothersome when biting, chewing or tightly closing the mouth. It may also include sensitivity to heat and cold. 

Additional signs of an abscess in the mouth include:

• Red, swollen gums
• Fever
• Swelling of the jaw or face
• Swollen lymph nodes in the neck
• Sinus pressure
• Visible boil in the gums near a tooth – which may rupture and leak fluid
• Dysgeusia (bad taste in the mouth)
• Halitosis (bad breath)