Complexion Files Included, you'll not suffer from that pesky green tint from the complexions sets anymore. Enjoy! and post your feedback since this is still on a test version.

Tools used:
GIMP

Requirements:
Mature skin texture and body for UNP UNPB 7BASE CBBE Vanilla (SE) by Maevan2

Description:
I've tried texture blenders but none seems to work for me, out of frustration I gave up and started fixing tones using GIMP, so if blenders doesn't work for you try this. Current version of head is Medium(Blemish) No scar, & No moles including complexions which now removes the pesky green tint, body used is young although theoretically should work with mature works with either young or mature body, thanks to Mebantiza for clarifying. Also take note that this is still on a test stage and hopefully it will work on yours and if it did, I will try to work with other mature face options if requested.

-Works on all female humanoid races
-Working but not yet tested for other users Does not work with other head complexion in racemenu aside from the first one. Well I've tried other texture mods and other complexion still makes head seam more visible because it changes the whole neck and face tone but I don't know, probably just on my side?
-Works with Ethereal Elven Overhaul (EEO) but only if you download the patch here Mature Skin Texure by Maevan2
-Works 99.99%, but ofc there's still head seam if you zoom in microscopically. See GIF image for more visual presentation.
-Works with UNP & UNP(B) and theoretically should also work with other body types e.g. CBBE, 7Base, & etc.


Installation:
Copy my file femalehead.dds, femaleheaddetail_age40.dds, femaleheaddetail_age50.dds, femaleheaddetail_frekles.dds, femaleheaddetail_rough.dds to your "\Data\textures\actors\character\female\" without quotes where your Skyrim main directory is located.
Back up the files listed above

Compatibility:
-Technically this should also work for you since I've tried applying this to a vanilla game/vanilla faces or heads with mature skin textures installed, also tested using WICO & TCM with mature skin texture installed.
-Totally not compatible with other face/body texture mods since this mod relies in mature skin textures but you are free to use it and experiment mix/matching with other texture mods and see if it yields result though it will surely replace your current head file and will use mature skin texture's head instead. ALWAYS BACK UP YOUR FILES

Credits:
Maevan2 author of Mature Skin Texture for assets