Here are my thoughts on helping out this situation:
1. Maybe there could be a generated skin texture without the photo and the
skin texture that is generated from the photo that could be combined with
a slider with different modes. For example the photo could be added with
a multiply mode, add mode, overlay mode.
2. Editing the Mask. I was able to take some of the highlights down a bit
using the adjust color option and turning down the brightness, but it also
effects the lips and eye brows. If we could edit the mask... never mind...
that might cause other issues.
3. Maybe the mask detects just the lips, eyebrows and nostrils that get added
to a generated skin color. And then we can "overlay" the skin on top of that
with an influence slider.
I'm just throwing out ideas... Or if anyone can make a tutorial in photoshop or action keys... please do