A couple of full head shots to show cumulative. Like I said it didn't take long at all to come up with the base head and neck skin, the mouth parts required the most work. Eyebrows are easy, it's the positioning sometimes that requires fiddling and second guessing. You can find plenty of open source brushes or reference. Pubic hair is a little more tricky but I have very good reference photos lol. Lash brushes are easy to find.

Adding all the little spots and imperfections, pores, etc can be tedious but I find it meditative busy work. Make sure you try to keep things on as many separate transparent layers as possible, you'll thank yourself later. Only bake down and final beauty blend when you are ready to make a particular master file. Keep all your templates as an over the top multiply layer and keep many selection sets. Especially the saved selections will come in handy later for detailed makeups. I usually use a combination of solid color filled selections that can easily be magic wanded ( lips and eye cavity areas) and many template based saved selections...