Plasma cell mucositis (PCM) is a rare benign disease affecting adults characterized by an erythematous mucosa, an epithelial hyperplasia, and a dense submucosal infiltration of mainly mature plasma cells. PCM has been treated with topical, intralesional, and systemic corticosteroids, antibiotics, and topical cyclosporin with unreliable results and questionable benefits. Here, we present a case of PCM, refractory to previous treatments, treated with i‐PRF (injectable platelet‐rich fibrin) injections. The infiltrations were performed once a week for 2 months. There were no adverse reactions to the treatment. The pain gradually reduced until the score of zero at the fourth infiltration, and the patient remained free of pain during the whole study period. Clinically, we did not obtain a complete healing of the lesion, but a reduced perilesional inflammatory infiltrate was observed at a distance. Therefore, we can conclude that i‐PRF has been effective in the management of pain in PMC but does not result in complete healing of the disease.