I am not sufficiently familiar with Accutane to pass judgement. But for a dermatologist suggest that acne has nothing to do with diet, is not entirely correct. I know that a zinc or B6 deficiency can cause acne, but so can hypoglycemia.
It may worthwhile trying out the hypoglycemic diet to reduce unwanted stress hormones that can cause anger outbursts. If Acne is the problem have a look at: