My Husband Is Diabetic, And Has Been Being Treated For

My husband is diabetic, and has been being treated for a diabetic ulcer on the left side of his heel of the left foot. When I was dressing his wound this week I noticed a black spot on his foot behind his big toe. I have seen spots like this on him before so I was not concerned. Today I was dressing his wound and to my total surprise the ulcer is completely closed and looks amazing but the black spot (smaller than a dime but larger than a pencil eraser) had elongated and is bleeding. He has vascular disease,vascular dementia, and is a right leg, below the knee amputee. We have a vascular surgery appointment next week.