Hi, How Do You Treat A Diabetic Leg Ulcer That

Hi,
How do you treat a diabetic leg ulcer that just won't go away. My husband has had 2 to 3 right next to each other on the same leg. It gets fiery red around the sores. The sores are about quarter size. His doctor wrapped his leg with some kind of medicated gauze and after a few weeks of doing that the ulcers cleared up but not the redness. After about a week the ulcers are returning. This is without the leg being wrapped.