Not to be over-speculative, but I think OP is probably referring to the rebound effects of corticosteroids which have been documented recently as related to skin conditions [1].
The "a skin rash I still struggle with until today" is probably skin thinning, too. Powerful steroids can permanently reduce the thickness of the skin, revealing capillaries in thin-skinned places like the face. It can look like a permanent sunburn.
[1] https://www.jaad.org/article/S0190-9622(17)32533-1/pdf