I don’t really have this issue but due to immunological funtimes I have had major allergies flare up just before a con. Ummm that may usually be due to naughty Epoxy Allergy use thugh I know I shouldn’t but at least once it was due to medication making my skin “photosensitive”. When your specialistwho prescribed the stuff makes a face you can be sure it’s all not good.
But yeah, also skin reactions that make flexible make up flake off. That is also fun. Still not sure what caused it as it was two different poducts months apart but the exact same spot affected.