I know a dermatologist who said taking vitamin c and e supplements is useless, thus shouldn't be taken. is what she said true? should i follow her advice?

Not useless: There is evidence that antioxidants help prevent and even manage some diseases. I'm not aware, however, of dermatological conditions known to respond to anti-oxidants. Vitamin C is quite safe and Vitamin E could be toxic but only at very high doses. The lack of evidence for efficacy does not prove that a substance isn't helpful, it means that there is inadequate evidence for benefit.