Accutane will change the amount of oil that your body produces. Ideally, oil production will be reduced and it will stay this way. Ideally, you will "cure" yourself of bad cycstic acne. If you are not using this med through your MD, I would keep the dose lower. 20mg is good. Moving to 30 or 40 mg is the most I would use and I would still get labs done to make sure that you are healthy. In the first 6 wks, you may find that acne gets worse. The sebaceous glands, under your skin, are pushing out oil. During this time, do your best to keep your skin clean and keep oil from building up/collecting bacteria on the skin. After you push through this period, the glands will dry out and with prolonged use, at a high enough dose, they will no longer produce as much oil in the future. The key is being on it long enough and at a high enough dose. If you went through a Dr, they may move you up to 80mg ED, and they will certainly have you do labs once a month. As I said, accutane is a very toxic drug. 

You will notice uncomfortable side effects. Your whole body will dry out. Your lips will crack. The inside of your nose will get dry. I stopped producing ear wax by at least 75%, especially in my left ear. Weird, I know. Using vasoline and or chap stick is going to make a differecne. You will also be more prone to injury. Muscle pulls and tendon issues can happen a lot easier.