This is really wild! I found a tutorial on natural skin layer shades (for C4D but hey, what works works!) that actually gave me an RGB color to work with. First I went for a hue fill, but I never love those because of the natural hue variations, so I tried just using my hue slider and matching the swatch as closely as possible with the main skin. The lips, at first glance, are still way too pink, but my selection tool insists that it's within 10% limits of the yellow. Weird! Now I'm wondering if I ought to invert the red for variation and overlay that as my lip color using the lip mask, and just use the hue fill for the rest of the skin. But check out this sliderized version: