Hi Doctor I Was Taking Tretiva 20 For 20 Days

Hi doctor I was taking tretiva 20 for 20 days but I got subs and effective has the my skin colour changing so I stopped using it but I felt within those 20 days that I was getting well from pimples but I stop suddenly due to some that is skin colour changing what should I do right now as that again started taking it off to kit for 5 days I have 25 capsules more