Dermatologic reactions are among the most common adverse events of antiprogrammed cell death‐1 (anti‐PD‐1) monoclonal antibodies agents and include maculopapular rash, psoriasiform rash, lichenoid eruptions, autoimmune bullous disorders, and vitiligo. Here, we present a case of a 12‐year‐old African American male with metastatic spitzoid melanoma treated with nivolumab who developed a mild lichenoid eruption that progressed to a severe case of lichen planus pemphigoides (LPP). Management was complex given the patient's age and history and included hospitalization for intravenous steroids, an intensive topical steroid regimen, methotrexate, and discontinuation of nivolumab. This case illustrates a rare but dramatic progression from a mild LP‐like eruption to severe bullous lichenoid eruption, most consistent with LPP, as well as the diagnostic and treatment challenges in the setting of a pediatric patient on nivolumab.