What Causes Itching And Swelling Around The Elbow Area?

i hit my elbow about3 weeks ago, the next morning the elbow was a little pointy. I found the elbow swollen and red the next day , the swollen area was about 7x6. I went to clinic (Sunday). The doctor took x-rays, did not see anything there-said it looked like celluitis. She said to apply moist heat and gave me a sulphur drug. A week has passed, the swelling is gone, exscept right on the elbow. There is some pain and it feels hot and the itching aroun and on the elbow is unbearable at times. I noticed the drug did say there could be a ras and itching.