I'd be happy to do it! just tell me, do you want it to be gradually getting darker, gradually getting hue-shifted, or both? I personally use a mixture of getting darker and both. Also, do you want it to have any kind of hue? SORRY FOR BEING SO LATE I JUST NOTICED ;-;

I'd like to help you, but could you specify a little more on how you want the skin shaded? Say the skin was red. Would you want to have someone shade it using lighten/darken, moving across the shades in that color, or shifting to other colors? (i.e. red to orange to yellow-orange, or blue to purple to magenta) I'd like to help, but I'd also like to know how you want it shaded.