If you have severe pain while defecation or bleeding per rectum.you may consult general surgeon/proctologist/me.

You are suffering from chronic anal fissure, in this case sentinel tag/skin is a normal thing, which occurs because of healing process. But perianal itching may not be associated with anal fissure, it may because of some form of worm infection. Srinkage/ stenosis of anal canal absolutely needs examination by a proctoscope to see the extent of stenosis, if stenosis is there you will need a minor procedure called Lord's anal dilatation to dialate canal.

Visit a Surgeon for evaluation and management Till then continue conservative management Keep area clean and dry