I've never used PC BhA, sorry.. but, I use Differin gel now and it tends to '' peel '' the skin.. so if PC BhA has that same type of effect then I wouldn't mix the two.. especially if you have slightly sensitive skin. Sorry I couldnt be of much help =] I only know about Differin.
hi there. i just started using the differin cream. my derm recommended that i use the differin cream before going to bed - spread a thin layer all over my skin (make sure it's at least 30 min after you wash/moisturized your face). i've never used the other one you mentioned, but if it's too harsh or drying then it may not be good since the differin will dry out your skin too. hope this helps!
Differin is a type of Vitamin A acne medication correct? If I'm right, I'd use the Differin maybe every second night and use the PC BHA on the nights you're not using the Differin.