PIE, Purging and AA doesnt work anymore?

I need all you Skin-Experts to throw your knowlegde at me. Please Help me 😄 So about 2 Months ago I learned about PIE and that this is the redness I have mainly on my right cheek. I started to use the PC Azelaic Acid Booster (every morning) and PC 2% BHA Toner (every three days) and saw results rather quickly and within 3 weeks my skin was a dream 😍 So clear and not a sign of redness anymore. Then I changed my cleanser to the CeraVe Cream-to-Foam (with SA in it) and startet to break out almost immediatley. I used it for like 4 days stopped it again and since then my skin is red again with a few breakouts. This was around 3 Weeks ago and the PIE is not getting better at all even though I'm back to the old routine. Can the Skin adapt to a Ingredient so fast that it is not working anymore (talking about the AA)? Or could it be purging and my skin is still getting the gunk out? All I want is the redness to disapear. It makes me feel so selfconcious. Thank you guys.