An abscess starts with a toothache. The pain gets worse, and you may get a little bump, which may grow bigger and cause more pain if not addressed. Sometimes, the swelling quickly gets big, and sometimes it progresses slowly. After a while, the swelling may burst by itself, and you get a bad taste and odor in the mouth. It is advised to go to your dental appointments regularly and maintain good oral hygiene to catch any cavities before they get big and become an abscess.