Quote - another way to do it, is avoid using colored textures at all, just greyscale maps
almost all shading work i ever do is with greyscale maps, usually being used as a multiplier to whatever color i choose, which has the added benefit of allowing limitless skin colors, rather than being bound by only a very small range near the color of the texture

another added benefit is it saves memory used by texture maps, since most skin keeps the same ratio in colors, (ie 200R/100G/100B vs 250R/125G/125B, why not drop the last 2 channels G and B, since we know they'll be 1/2 of R?) so leaves 2/3 of the texture file to be replaced by bump, spec, or something else, then have 1 of the values used to control each thing in shader room, one of many ways to use texture maps to store more useful info :)

That's actually the correct way to go about it, because it allows the shader, which can be light-independent, to drive the skin color in any giving lighting situation.

I haven't used Carrara since early on in my 3D experience, but the same theories apply to almost any 3D application.

It's good practice, for example, if you are going to use subsurface scattering in your skin shader, that you at least reduce, or sometimes completely get rid of,  any red color channels in your diffuse texture map before hand, since your shader will be used to drive the subsurface scattering, based on the lights in your scene, and provide the adequate skin "reddening" in the final output.  I used to consistantly make the mistake of using full color diffuse textures with SSS in some other apps, and the resulting skin always needed extensive color correction for being far too oversaturated.

It also helps if you are able to use greyscale "control" maps to help drive the scattering depth, etc.  Proper texture maps play a vital role in realistic rendering, especially for something as infinitely complex as human skin.

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Tools :  3dsmax 2015, Daz Studio 4.6, PoserPro 2012, Blender v2.74

System: Pentium QuadCore i7, under Win 8, GeForce GTX 780 / 2GB GPU.