Retin-A question?

My dermatologist prescribed Retin-A 0.05% cream because of my mild breakouts...bumps and clogging on forehead. I've used it nightly for over a week and noticed new breakouts on cheeks and jawline. I know this is the purging process therefore I'm not too concerned yet. I've been reading and researching and hear a lot of great things about retin-a but I have one concern. Does it really make you break out horribly after you stop using it? How long does an average person have to stay on this medication for acne? I am 27 years old with oily skin so I know my breakouts are from the over active oil glands. But with age skin tends to get drier so I'm hoping that I wouldn't have to use retin-a forever since it is so expensive and there are a lot of side effects. Thank you