You can stop if you want to I believe. I am taking accutane as well, but luckily I'm in my final two weeks of treatment. I wish I had never taken it at all because since I started I realized all the natural CURES that exist that are permanent and better than the bandaid that accutane puts on the acne. I am going to take the last 2 weeks of pills though since I paid for them...lol Probably not good to keep taking it, but I have some major detox plans for after I stop the treatment.
If I were you I would look into natural cures and consider making some diet changes. There is a wealth of information on this website alone including Barefoot Herbalist's free e-book called "Book I".
How long have you been on accutane? It's not helping at all?