A 40-year-old male presents to the clinic with a painful, re…

A 40-year-old male presents to the clinic with a painful, red, swollen area on his leg that he believes is due to an insect bite he received two days ago. On examination, there is a 5 cm area of erythema with central punctum, warmth, and tenderness. Which of the following is the most appropriate next step in the evaluation and management of this patient?