Suggest Treatment For Swollen Ankles

Hi, i was in a car accident 18 months ago and gotten 9 screws and a plate placed in it. The weather right now all of a sudden became really cold and my ankle has swollen up! i can bearly walk because it hurts to put any pain on it. I dont know why this may be. Can you figure out why my ankle may be swollen and what i could do about it?