Erythema Migrans — Lyme Disease

A 35-year-old man from Himachal Pradesh presents with a 10-day history of an expanding rash on his right thigh following a hiking trip. On examination, he has a well-demarcated annular lesion with central erythema, a clear ring of partial clearing, and an outer expanding red ring (marked **A** in the diagram). He is afebrile but reports mild headache and myalgia. He denies pruritus or pain at the lesion site. What is the most likely diagnosis?