Quote - ... what about the scatter  node?

 

When I try a blender or adding another color_math, it renders darker than the skin should be ....

Right; you just plug you color_math node into your Scatter node's "color" input - the same place you have your torso map plugged in.

Oh and you're better off having only the image map plugged into the Diffuse channel since Poser can not preview the makup overlay.

 

That ought to do it!