I Have A Tear In My Achilles Tendon. Been Doing

I have a tear in my Achilles tendon. Been doing physical therapy. During my therapy I have a patch like bandage where they put dexamethasone on a gauze spot and place over my tendon area. There is a battery on the patch. Once on they pull a small tab and I wear for a couple of hours. It is like a tiny tens unit. Can you tell me the medical name for this procedure? And do they ever use this for the patient at home