It was the most miserable four months of my life. If I sat for more than a minute or two, I was so stiff when I got up to my feet that I could barely move. Turning over in bed at night meant that I had to grab the sheets and pull myself over, and it was horribly painful. I felt like I had some kind of muscular or skeletal disease. It cleared up my acne, and I don't really have problems with acne now, but it also thinned my skin and dried up my sinus mucosa to the point where I had nosebleeds two or three times a week. Thirty years since then and my nose is better, but I still have problems. Oh, and I was wearing extended wear contact lens at the time, and my doctor neglected to tell me that my already-dry eyes whould dry up even more. My contacts suctioned to my eyes, and I almost ended up in the hospital because my eye doctor though I had a highly-contagious eye disease. I quit after four months because I couldn't handle it any more.
That stuff is poison and should only be used in the most drastic situations. Surely today there are other treatments for cystic acne that would be better than this.