Suggest Treatment For Bruise In By Buttocks

Hi , I am sure one does not go hand in hand lol but I had a ct w/contrast and severe allerigic reaction . I know warm sensation IS normal. I got hives bad,swelling shortness of breath etc. However I have a huge unexplained bruise the size of a tennis ball on buttox which if actucally looked at closely has lines in it like from fabric of clothes. Bruise is obviously tender sore ,is there any corrolation like getting burned?