Green?

I know why  shyness make one blush bright  red .It’s to make people steer clear but why does envy make one green?Is it a metaphor as it’s sickness that usually makes one go green.Envy may be  sickness.Is that it?
I went white all over  when he rejected me.I looked as if I was dyed
She has the blues but it’s not obvious unless you know her really well.Like if she cuts her finger.I blame Edward the 7th.He’s dead, you see.