S.-
I went on it when I was 16 and it worked wonders. I also had cystic acne. It honestly was a miracle drug. Although very, very strong...it does work and I know how you feel with regards to acne--it hurts, it makes you feel ugly and is just plain annoying.
I am now 31 and having my second child. I now have gotten acne with both pregnancies...but just minor blemishes...not the cystic kind. After my first pregnancy, my skin was clear again. With this pregnancy it is pretty clear only a few minor blemishes every now and again.
I would recommend it however, you have to be aware of the side affects. It caused me to have very, very dry skin and my lips would peel.
It can also cause depression...although, that was not a side effect for me.
Also, the doctor will make sure that you are using two forms of birth control, as it will cause severe deformation of a child if you were to get pregnant. That is really the biggest concern.
I believe I was on it for 6 months. When I first took it back in the 90's it was kind of a newer medication, I believe...so it has had more time on the market now and more studies done.
I just remember how good I felt about myself after my skin was clear...it was just an amazing feeling.
Good luck!