Can you use facial oils/ coconut oil while on accutane/ roaccutane. What should I use?

I am in my third month of accutane, my skin and lips are starting to get really dry. My skin is flaking and lips are peeling. My dermatologist has said I cannot use any oils on my face just an aloe Vera gel or oil free moisturiser as oils cause oil like cysts. But when I have researched it nowhere else says anything about using aloe Vera gel as a moisturiser or that oils are extremely bad. I was just wondering which skincare products are recommended and which should be avoided completely.