In Photoshop, under select menu > color range
In the drop down box up the very top, there is the option of 'skin tones'. There is also a 'detect face' check box.

Anyway, none of those things do what I want. I wanted to know if there is some 3rd party plugin that can make a selection around a human face AUTOMATICALLY, without any input from me. I did a Google search but I couldn't find anything like what I want.

The reason I'm asking for this is because I photographed a model who is fairly pale skin and I wanted to make his skin more tan. The photos are shot in a studio, so the lighting is consistent through hundreds of images. His face is slightly darker than the skin on his chest, arms, legs. I want to create a Photoshop Action to batch edit across hundreds of images and make the skin more tanned in all images. I can't do it if his face looks unusually darker post batch editing. So if I had some 3rd party action that can recognize faces and give me a selection in that area, then I can feather the selection and add a mask to the tan skin layer to dial the effects down so that the face looks more similar in tone to the rest of the body. Basically I don't want to go through hundreds of photos one by one and edit the face one at a time. 

BTW, I also tested out using a gradient mask to apply only to the top area of the image, where the model's head would be. This sort of works, as long as the model's head is in the same vertical position in most images. Though in some images his head does move quite a bit lower in the frame of the photo.

Every time I've shot hundreds of images I've looked at them and there are just a few at most that are the best images from the shoot. I narrow those down before I do any sort of retouching.

If you are consistently getting all "best" images then perhaps shoot a dozen or so and call it good?

Seems like a lot of extra work to process so many if few will be used.

As to your question, that would be an extremely difficult Action to create, in part because there are so many different variations in hue on a single human and partly because there is a huge range of human skin tones. Last but not least, there are often similar colors in other objects in the image.

If you look at the Channels (red, green and blue) you should notice that skin contains all of these colors.
While there are cameras that can focus on eyes in faces, that is a much simpler task than selecting only the skin of a person precisely.

I figured it out. In Photoshop CC, first duplicate the background layer, then I open up the liquify program. Then I go to the face section and just widen the face to 100%, then press okay to exit and accept the liquify changes. Then I change the blend mode to 'difference', obviously only the face area is different between the two layers. Then I create a new layer on top and do 'merge visible'. Then I use the curves to brighten this layer a lot. Then I use "select menu> focus", which now selects the face area. Then I add feathering of 30 to that selection. Then I make a new layer and fill it in. Now I have layer with a filled in color of where the face is. Now I can use that layer to load up the selection and use it in my photoshop action to batch edit. And it doesn't matter where the model's face is from image to image, because photoshop knows.

or you could just use the pen tool and draw a path around the face, convert the path to a selection and save the selection.