NOTE 1 > You can find all the information you need about 2nd Face here:
https://www.renderosity.com/forums/threads/2990766/2nd-face-a-cool-way-to-change-a-figures-face
NOTE 2 > This product requires the free installation of at least one of the smart head props of 2nd face that are available here:
https://www.renderosity.com/users/3Dream/freestuff
INSTRUCTIONS:
After adapting 2nd face to the figure you are working with, simply go back to the 2nd face POSE directory and you will find a folder named Arnold MATs.
It is within this folder that you will be able to choose between 60 skin tones so that you can find a tone suitable to your scene.
In the Materials directory you will also find the same MATs but in my opinion, you can use them when you intend to use 2nd face as a independent prop, that is, without adapting it to a figure.
If you have any question about this product please contact me. Thank you.