A 30-year-old female presents with painful, red nodules on her shins that appeared 5 days ago. She also complains of fatigue, fever, and mild joint pain. She recalls a recent sore throat 3 weeks ago but denies cough or gastrointestinal symptoms. Physical examination reveals tender nodules on the anterior shins. Her ASO titer is elevated, and a chest X-ray is normal. What is the most likely diagnosis?
