Left cheek suddenly swollen need to find the cause of the cause of treatment, may be acute parotitis, buccal gap infection, wisdom teeth pericoronitis, need to be treated with drugs or surgery. 1. Acute parotitis. Acute parotitis can be caused by bacterial or viral infections when the body resistance is low, with redness, swelling and tenderness in the parotid area and swelling in the front of the earlobe. For viral infections, antiviral drugs such as acyclovir and ribavirin should be used, and for bacterial infections, antimicrobial drugs such as ceftriaxone sodium should be used. 2. Buccal gap infection. The left cheek is swollen, it may be buccal gap infection caused by periapical infection, for touching with fluctuating sensation, need to carry out incision and drainage after anti-infection treatment, use antibiotics, such as roxithromycin, amoxicillin. 2. Wisdom tooth pericoronitis. Acute wisdom teeth pericoronitis attack can also cause buccal swelling, generally local saline rinse after iodine povidone, turn to the chronic phase after considering the removal of wisdom teeth. For the oral and maxillofacial abnormal swelling is recommended to the hospital in time to avoid aggravation of the condition, the use of drugs under the guidance of the physician.