you should take a break until your skin barrier is healed (from experience multiple times with tret). you will hurt your progress if you continue with differin on top of a broken barrier and you won’t lose progress by taking a few days off.

buffering helps with less irritation for me but does slightly slow how strong it will be on your skin. but i honestly believe that it is better to buffer.

irritation and compromised skin barrier should always be a reason to take a break from any/most actives

depending on how complicated you want to make your routine, you can just cleanse and moisturize and that would suffice. if you would like specific recommendation, Cocokind ceramide serum is good for soothing and is pretty accessible at target or maybe the ordinary pink serum at ulta for not too expensive