2 questions-
Is it better to use in the am or pm or does it not really matter?

Can I still use my glycloic acid cleanser before and Afirm 2x (if pm) or CE Ferulic (if am) afterwards? I am prone to slight sensitivity (redness/itchiness)/dryness) in the winter.

I've used various scrubs sporadically in the past, but not microdermabrasion. I'd like to add this to my regimen about 1-2x per week, but am kind of scared of having a reaction. I began using CE & Afirm a few months ago. Please advise!

Many thanks in advance.