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You are seeing a 10 year old boy with 3 days of submandibular swelling. On exam, he has a 2cm x 3cm tender swelling in his right submandibular area. The parents report that the has had this twice before, each time treated with amoxicillin-clavulanate and resolved. He is afebrile.

Which of the following is the most likely history or physical examination finding?