I tried promox that has retin-A. It burnt my scalp like hell. I used similar product without retin-A before without any issue. So it must be the Retin-A.
Yes Retin-A will do that to your skin/scalp, you need to start with very low concentrations then build up and as the skin gets thicker/smoother, the skin gets flaky and you need to peal it. This is what I've read, haven't tried it myself.