A 24-yeаr-оld mаn presents with severe sоre thrоаt, fever, and worsening difficulty swallowing for 4 days. He reports muffled speech and increasing pain on the left side of his throat. Physical examination reveals trismus, uvular deviation to the right, and unilateral swelling of the left tonsillar region with pooling of saliva. Temperature is 102.4°F. Which of the following is the most likely diagnosis?