A 28-year-old woman from Mumbai presents with a 2-week history of sudden onset of numerous small, erythematous papules with fine scale on her trunk and proximal limbs. She had an upper respiratory tract infection 3 weeks ago. On examination, lesions are 3–5 mm in diameter, teardrop-shaped, and scattered over the body. She denies any joint pain. What is the most likely diagnosis and the expected clinical course?