I have had a dermatologist check out the discolored spot that was there, and I was told it was non-cancerous. Two weeks ago the spot peeled off and a large blister filled with clear sebum appeared in it's place. I don't know what to think? Have you ever heard of such a thing? I am elderly and diabetic, so this is a concern. My doctors thought nothing of the spot and my primary does not find it urgent, I am just curious of what has happened to me?