Seen in the ED: Facial Pain and Swelling, Sour Mouth

History of present illness. A man in his 50s presents to urgent care for 2 days of right facial swelling and pain. He denies any fever but does state he has a bad taste in his mouth.

Vital signs and physical examination. Vital signs are normal except for mild tachycardia. Examination is notable for facial swelling on the right. Dentition looks good.

Initial diagnostic testing

Labs: WBC = 14, BMP normal, CRP = 20

Imaging: CT scan is done. Two cuts are shown below.

What is the most likely diagnosis?