Allergic reaction to bactrim?

at first i had strep throat and what the doctor told me was a staph infection from a belly button piercing. they gave me a bactrim and another medicine for strep. within three days i started getting itchy and then red bumps eventually started all over my body. i stopped the bactrim and still got worse so i stopped the other antibiotic also. i got a steroid shot and the doctor gave me prednisone. i went to a different doctor and then they gave me a new antibiotic and i only got itchier so i stopped that one also. now i'm only taking prednisone and hydroxyzine for the itching, which helps somewhat. when will this rash go away!? its so itchy and ugly. and its ruining my summer. its been 7 days since the hives i guess? started to appear.