Everyone's skin has undertones of either yellow or pink. A simple way to find out the color of your undertone is to check your veins on your wrist. If your veins appear blue, then you have a cool pink undertone. On the other hand, if you veins appear green, then your skin has undertone of warmer yellow. If you're lucky enough to have veins that appear to be both green and blue, you are the proud owner of a neutral undertone.