Pain after fissurectomy , lateral anal sphincterotomy and anal Dilatation usually lasts for about two weeks and rarely beyond that. If the pain persists  beyond this period you need to consult your surgeon once again. The pain is prolonged especially if your surgeon did not apply marginal sutures and instead left the sphincterotomy wound open.

It can be normal also if your operating surgeon say so. You can apply ointment hemolit bd with sitz bath