This patient received an injection for restoration of an upper tooth on the left side. Two days later the patien returned with a severe hematoma involving the maxilla and the mandible.

A hematoma, a blood clot resulting from hemorrhaging into surrounding tissues, occurs if a muscle fiber is penetrated or a blood vessel is perforated by the injection of the anasthetic into the lower jaw.

Usually warm moist heat applications, stretching exercises, and time is sufficient treatment.