Sulfamethoxazole and oily skin

I was prescribed sulfameth by a dermatologist to help dry out my oily skin as a teenager(15years ago). After a week of taking this medication orally, I noticed I had bruises that i could not remember any injury causing. At the time I had braces on my teeth, and one morning after noticing the bruises on my skin, i woke up and noticed blood blisters on the inside of my mouth and tongue! Sulfameth was the only medication i was taking at the time. I went to my dermatologist to get his opinion, after which he sent me immediately to the hospital. Turns out, I was on the verge of internally bleeding to death. I had to stay in the hospital for a week, where i was treated with a steroid to boost my red blood cell count because it was deathly low. Had i not noticed the bruises, and blood blisters in my mouth from the braces, I might not have known.