The order to build it in
- Cleansing without the squeaky-clean feel: a BHA cleanser morning and evening, no more often.
- One active at a time — salicylic, azelaic or an AHA/BHA serum. Two at once gives irritation, not double the effect.
- Light hydration: a gel or cream without heavy oils — over-dried skin makes more sebum.
- Sunscreen every morning: marks left by breakouts darken in the sun and stay for months.
What not to do
Do not layer retinol with acids on the same evening, do not scrub over inflamed skin, and do not replace the whole shelf at once — you will not know what caused a reaction. Give the set four to six weeks.