I am a diabetic and by my belly along waist line their is a large nickel size sore deep in purple and then it turns to red looks like its getting better then it turns back to a deep purple color and this cycle contunies. Any thoughts?

My husband died of complications of Diabetes.

Get to a Doctor - now! This is nothing to ignore and could turn into blood poisoning in, literally, a flash. Your skin is breaking down and the situation must be addressed by a Physician.