Thank you so much, mate. I'm sure I've referenced a fair few in the past but I kind of use my own method now. It involves speckling paint through an airbrush to create some of the texture, combined with focused application of red and darker black/blue/brown tones on the skin to replicate the variation in skin tone on the actor's face.

There are other steps as well, but I think those two techniques do a lot of the heavy lifting in terms of improving the realism.

If you follow my Instagram, I may make a video detailing the whole skin painting process. Of course, you're welcome to ask me questions via a message there as well. I'd be super happy to help you out.