if your skin is that bad why not beg the derm for keflex to take for 4-8 weeks? that stuff worked so well i stopped breaking out in 5 days after taking it. it saved my life and my skin from anymore scarring so it was totally worth it. i was supposed to start accutane around the time i asked for keflex so that was like my last shot. so glad that it worked i never had to go on accutane. i am on 100mg spiro a day and have been so for over a year. i will say every single time my dose was upped i got a bad breakout it was awful. ugh!
its fine to take spiro and accutane together because like my derm said the accutane would have cleared me up but that i would most likely start breaking out after i got off of it unless i stayed on the spiro since my acne was hormonal. anyway keep on the spiro and ask for the keflex. i tried bactrim about 6 years ago and had a bad allergic reaction from it. took 2 weeks for the reaction to really set in and when it did i had a 103 degree temperature and had to take steroids for 6 days. no fun there but you wont know if you are allergic until you try it. good luck to you - keep your chin up!
one more note if your skin is bad enough the derm can give you prednisone to calm everything down.