May or may not have pain
Bacteria can get through the tooth and travel down the canal until they come out into the bone. This will usually follow a bout of pain at some stage, though sometimes the swelling can come years after the original tooth pain. Dental swelling needs to be taken seriously as bacteria in the head and neck can travel to the brain and cause serious problems. Attend the dentist ASAP. Drainage of pus is the primary concern. The tooth may be removed, or root canal treatment can be started ASAP. Antibiotics are helpful when there is pus involved. Do not rely on antibiotics alone. The infected tooth must be treated.