First I opened up the Hue/Sat editor (Image > Adjust > Hue/Saturation) and adjusted the hue slightly to the right (adds more yellow) adjusted saturation up more (adds more color) and lightened it some. I closed that and then opened up Brightness/Contrast (Image > Adjust Brightness/Contrast) and lowered the Brightness some (lowring brightness is not the same as adjusting the lightness with Hue/Sat. If you become comfortable with the differences you'll know better when to use one or the other). And finally I went back into Hue/Sat and added a bit more saturation.
At this point I felt that the new photo of the ear and side of face was close enough to the original skin tone that I could work with it
Now I was ready to start Free Transform on the image to rotate, move and scale it into place
Since I didn't just copy the ear, I got the side of the face as well, I can use some of that to crestore the skin texture to the smudged areas from earlier.
For the ear I had to do a lot of adjusting to get it to fit on the model correctly. You'll probably have to be switching back and forth between max and photoshop frequently.
The quickest way that I've found to resave my texturemap file for max is as follows:
I leave the texture.bmp file open in phothsop, minimized. Everytime I want to test to see how my texture looks in max, I turn the uvref layer off in my main .psd file. I make sure I'm currently selecting one of the visible layers, I select all (Ctrl+A) and then I Copy Merged (Edit > Copy Merged |or| Ctrl+Shift+C) This will copy the entire visible image to the clipboard and you can go to your texture.bmp file and just paste the whole thing in. Flatten and save and now you can view your progress in Max
From this point I just kept smudging and rubberstamping the skin around the head, trying to maintain some consistency and avoiding blotchyness. I grabbed a bit more skin reference from another photo source, did some hue/stat and bright/contrast adjustments to get it to match the skintone and I used it for the neck.
I didn't worry too much about the back of the head since I usually cover that up with hair
I don't honestly see it being all too important a step with this particular model, but I'm going to cover this step because I use it with all my other texture painting.
Whenever I want to add in shades or highlights to a texture I NEVER do a direct burn/dodge onto the texture itself. If you do that, you can't smudge, erase, or adjust it without messing up your texture image underneath. So instead I use adjustment layers.
Click on whatever layer you have directly underneath your UV reference layer - it doesn't matter what it is, all that matters is that it's 2nd from the top.
Now Click on the adjustment layer button at the bottom of the layers window. A menu will pop-up from that. Choose Hue/Saturation... from the list and it'll create a new layer and bring up a Hue/Sat window. Pull lightness way down so everything is dark, and adjust the hue slider a little to one way or the other - but just a small amount.
Click OK. The way an adjustment layer works is with Black and White. If you look at the layer itself, the little adjustment icon is all white right now. We need it to be black so Go to Image > Adjust > Invert. Now your whole texture looks normal. If you choose the paintbrush tool, you can only paint in greys. White to Black and anything between. If you pick a grey around the middle and paint on the layer, it'll put in about 50% of the hue and lightness changes you set before. Paint with white and it does the full 100% of the adjustments. Every layer underneath the adjustment layer is affected by it, but you can paint, smudge, and mess with this one as much as you want and it will never physically change the laters below it
I use adjustment layers all the time for painting in cloth wrinkles where there are none, when I'm texturing clothing. I usually have one or two darkening adjustment layers and a brightness layer (I usually use a brightness/contrast adjustment layer when I want a highlight adjustment).
There isn't too much need for these sort of things right now, but it can still add some more depth and detail to the image if done properly