A 32-year-old man from rural Maharashtra, diagnosed with lepromatous leprosy 8 months ago, presents with acute onset of painful nodules on his shins, fever (38.5°C), and painful swelling of both knees and ankles. He has been compliant with multidrug therapy (MDT) for the past 6 months. On examination, erythema nodosum-like lesions are noted on the extensor surfaces of the legs. Histopathology shows neutrophilic infiltration with immune complex deposition. What is the most likely diagnosis?