If the oil production returns to normal after accutane is stopped, doesn't that mean acne will return? so how come accutane is considered the only medication to cure acne permanently? thanks

Its not: isoretinoin targets systems that involve vitamin A in their control processes, and that's probably how it shrinks sebaceous glands. But Accutane, the orally ingested form, also gets to ALL systems; luckily it doesn't have a major effect on the 'big A system'..vision. When you stop Accutane, the sebaceous system can recover, and you could get acne again. Usually, your body has moved on.