i was confused because bha and vit c are both acids so i didn't know which to use first. i have muac vit c and psf bha. i need to go back and look at the ph's. my skin is doing well again. i'm just focused on two dark marks on my check from when my skin wigged out in the fall. i'm using hydroquoinne to speed that along. i'd like to be able to not have to wear concealer to cover those spots by spring.