I found a non-Myers mask that I was considering buying if I could get it for the right price. But I found out that the seller used makeup to give the mask a more realistic flesh tone look. He said he could easily wash the makeup off before selling it to me. But what irreversible damage could have been done to the latex already? I would imagine that the oils in the makeup could have started a decaying process by now that basically can’t be stopped. Any thoughts?
I would lay my hand on a bible and swear in court that I once heard a rare interview with Tommy Wallace that said he touched up the hero with white clown makeup because the spray paint was flaking off. My point is, look at the hero. It’s not in good shape and I think makeup is not good for latex
Yeah I’d steer clear too buddy. It would be different it it was just touched up slightly (Pretty Woman Leatherface for example) but the whole mask? Yikes 
“Oils: The silent killer. Moisture lotion, makeup, and any other oil based products that may come into contact with your mask while in use will most definitely degrade its quality over time. However, it will take a long time for this to happen.”
-Morbid Enterprises, https://morbidenterprises.wordpress.com/2014/11/13/how-to-care-for-your-latex-halloween-mask/
In addition, most makeup contains paraffin and petroleum in both liquid and oil forms, as well as white oil and other mineral oils. I’d steer clear, makeup is very bad for latex.