Aims and background: Oral submucous fibrosis (OSMF) is a potentially malignant condition of oral cavity. Optimal dosage of local injection of corticosteroids with hyaluronidase is an effective treatment. Case description: A 34 years’ old male, diabetic patient reported with reduced mouth opening. He had a tobacco chewing habit. He was thoroughly examined and diagnosed with OSMF. Due to diabetes, he was advised only hyaluronidase injection. After 4 sessions of intralesional injection, he started developing facial edema after every session that subsided within 48-72 hours. Conclusion: The present report is to discuss a complication of intralesional hyaluronidase therapy. Clinical significance: Hyaluronidase can be administered without corticosteroid in OSMF patients with diabetes keeping in mind the adverse reactions that could happen and how to manage them when encountered