Suggest Treatment For Bruising On Leg After An Injury

I fell and scrabbed my leg 4 weeks ago. The area that was injured has become black and is red around it. My leg hurts in the area that is red. It is so painful that I wake up in the middle of the night with the pain. Nothing can touch the black area or close to it because I yell with pain. I put neosporin on and cover it with a huge bandaid. I wash it very carefully every day with soap but I am getting nowhere fast. What else can I do? My friend remarked that my wound looks like it is rotting.