You need to at least moisturize while on accutane or you'll shrivel away. But beyond that (and sunscreen), I guess you're wondering if you should try not washing your face? I wouldn't personally advise it.

I would advise against it. There's no need to do cavemen if youre on accutane and it will likely hinder your process. Your skin will get very dry and you should always cleanse at least once a day to remove dirt.

accutane will almost 'reset' your skin, so its good to just use a basic cleanser and moisturizer (such as cetaphil) so that when you're off of the accutane your skin is used to a calm and gentle routine