A 32-year-old woman presents with severe anal pain during and after defecation for the past 3 weeks. She reports bright red bleeding on toilet paper and describes the pain as sharp and burning, lasting 30–60 minutes after each bowel movement. On examination, a visible tear is noted in the posterior midline of the anal canal. Digital rectal examination is extremely painful and reveals a hypertonic internal sphincter. Anoscopy is deferred due to severe pain. What is the most appropriate initial management?