I have suffered from horrible cystic acne since I was 14 until I was 27 - even at 30 I still get flare ups. I never tried accutane - I was too worried about the side effects!
I have taken tons of different meds - between my eczema and my acne, I'm surprised that I have any skin left at all. I found that taking a combination of soladyne (sp?), a retin-a derivative in the morning, and some sort of topical sulfa drug at night worked best for me. I also change my pillow cases every day! However, everybody has a different body chemistry - so finding what will work will take some time. Also waiting for the drugs to fully work will take some time. Using this combination (which has kept me relatively clear for the past 2 years *knock on wood*), I finally saw the desired results after 12 weeks. Also, with many of these drugs, my derm told me that I would clear slightly, flare up big time, and then start to clear completely. So, flaring up after a week or two after starting is normal - it will take time to see the desired results. I would have to echo what everybody has said about the message boards at acne.org - they let me know that there were other people out there who were going through the same thing.
In addition, I know that many dermatologists will have "emergency appointments" set aside for people who have terrible acne. They understand how people can suffer from acne and if you explain over the phone that you or your child have large cysts covering your face, they will want to get you in there and help you out. They sometimes will even give cortisone shots in the cysts to reduce the swelling (they will not do this on a regular basis, but if you have a prom or wedding coming up, this is the time to do it.)