D. Craig Flory posted this at Adobe Forums today addressing the same subject:
(I have not tried this. I don't face this problem much in wildlife photography....a bird having a bad feather day just makes the pic more interesting. Funny how that usually doesn't really hold true for pics of people.

)
... retouch on the green channel only. Open your image. Double click to make it layer zero & then dupe the layer. Now go to the channels palette and turn off the red & blue channels. Use the clone tool at 20% on lighten. Once you have it the way you want it, click Layer > Add Layer Mask > Hide All. Select the brush tool with white as the foreground color. "Paint" back the retouching you did at about 20 to 30% opacity. By doing it this way you can control the contours of the face and not make it look to flat.
I hope this helps.
Lexi