A 38-year-old woman from Bangalore presents with acute severe burning pain in the distribution of the right trigeminal nerve (V2 and V3 branches) following a dental procedure 2 weeks ago. She describes the pain as lancinating, triggered by light touch and chewing. Intraoral examination reveals no obvious pathology. MRI of the brain and skull base is normal. She has failed topical anesthetics and NSAIDs. What is the most appropriate next step in management?