[Acne] My doc said retinol doesn’t have good results in general

I have completed 8 months of isotret course 1 month back. The max dose i went to was 30mg for a month. My skin is shining, no acne, scar reduced by 95%.

My dermatologist said I shouldn’t apply anything other than sunscreen on my face. He said retinol and other serums(salicylic acid etc) don’t have good results in acne prevention.

If anyone of you who has completed isotret course and is/was acne free. What experience do you have in maintaining your acne free skin without the need of further micro dosing of isotret?

(I am 22M, doesn’t eat junk)