Observation: A 24-year-old man was referred to the dental emergency department for the management of a left submandibular cellulitis. The origin was a mandibular third molar. Drainage of the cellulitis and avulsion of the tooth were performed under general anesthesia. The follow-up was marked by a secondary infection of peri-zygomatic hematoma requiring a second drainage procedure. Discussion: The origin of the hematoma was a tear of the insertions of the mandibular elevators secondary to the trismus. The patient underwent two back-to-back general anesthesia procedures with tight trismus making induction and intubation difficult. Conclusion: A two-stage treatment with initial drainage and delayed avulsion after improvement of trismus is discussed.