Using ffmpeg filter to change skin tone
Solution 1:
The selectivecolor filter can be used for this purpose.
If you have a problem with pink color, you might want to adjust the reds primarily:
selectivecolor=reds=.5 -0.5 .5 -0.3
You can also tweak the filter with Photoshop, using the Selective Color adjustment:
Here, you can save the preset as an asv file and load that in the filter instead of manually specifying the parameters in the ffmpeg filter options.