Violaceous Nodules on the Right Leg and Foot

This is the authors' abstract. We don't add key points for this paper.

A patient with a history of bullous pemphigoid treated with oral prednisolone presented with multiple round, dark brown to violaceous-colored firm nodules on the right leg and 2 nodular masses with hemorrhagic crusts on the right foot. Complete blood cell count and creatinine and liver function test results were normal, and results of HIV antibody testing were negative. What is the diagnosis and what would you do next?