Thank You. I Was In A Car Accident 3 Weeks

Thank you. I was in a car accident 3 weeks ago and hit my right thigh quite hard on the steering wheel. That bump and bruise have have gone away, but sime of the bruise has traveled down toward abd into my ankle. It is red, swollen and very sore when I try to stand on it. Went to Urgent care, and they sent me for a Doppler? test to check for a blood clot, but according to the results, there is no clot. That was Thursday afternoon and now it is Sunday morning, and I am still having the redness, swelling and extreme soreness in that area. They are treating me for cellulitus with antibiotics and they gave me a shot of an antibiotic when I was in the offic. Do you have any idea what's going on with this problem?