Well, I suppose when you turn white as a sheet (assuming you have the sort of skin that is grey/pink to start with) it might be from shame, though more typically I'dthink it'd be fear, and shame you'd be likely to bluish red.
It's always struck me as odd about "red" in this context - the only people who actually are red much of the time are Northern Europeans. I can't believe anybody could ever have actually described a Irishman withna scarlet pelt after working out in the sun as a "paleface".
The Caucasus is a mountainous region between Europe and Asdia the other side of the Black Sea. Armenians and Georgians and so forth. I don't know the last time I met a Caucasian, must be forty years or so.