Is this fat necrosis? When will it heal? What is the treatment? (Photo)

I've had this spot with drainage for about a week. At first I used peroxide and sterile saline spray as told by my ps but now I'm just using the spray. I change the bandages every 3 hours and there is a lot of drainage. I go back to ps in 3 days. Just want to know what to expect with treatment. Photos are like 4 days apart.