During acute stress, a fight-or-flight response constricts blood vessels in the skin to redirect blood flow to muscles, potentially making the skin appear pale or gaunt.

“in the immediate phase there's a big shift in blood flow to the skin and when you're feeling you know very stressed out immediately there's a fight ORF flight response that constricts the blood vessels in our skin to shuffle them to muscles and places where we need to our body thinks we need to utilize them more that's why when people are really stressed out they may look p haale or gaunt”