here is an example of what colors should be used in a common human skin.
Saturation in the midtone as orange(hot) or red(cool), plus the environment light.
purple and red plus skin tone for mouth, except when with lipstick.
red on cheeks(not normally), nose and ears, where the skin is thinner and
the blood makes it appears red.
eyes, any color, nomally black, brown, green and blue.
and the beard is gray to green, for males.