Ears are so thin, the sun can go straight through them, and they glow like crazy. Thanks to Angela Beransky for allowing me to use her lovely backlit photo for this demonstration.
This is the handiest fix I've found. Simply add a Hue/Saturation adjustment layer, and click the "Colorize" box:
Then fiddle with the sliders. Usually I find it's necessary to push the Hue slider a little, and the Saturation slider a lot. These are the numbers I used for this one:
Then mask. Here's the result:
Note: While this method works well for ears, it doesn't work for hair. If Angela wanted to tame the glowing hair, another method would be necessary (probably Channel Mixer).