Color adjusting with brush in LR4

I know how to add color with the brush. What I am wanting to do is selective color adjustments with the brush. Further down the tool pallette, there are sliders to adjust hue, saturation, and luminance for different colors (red, purple, green, yellow, etc). These sliders adjust globally. For example, can I turn down just the reds in a face only in lightroom? I want to turn down the red saturation just in a face without affecting anything else.

I've searched all over YouTube for a video that does this, but cannot find one.

No, adjustment brush wont allow you to make individual colour adjustments unfortunately. I think your only option is to make two images and then take them into PS/PSE and use a layer mask to reveal the face you want.

You can't do a local selective color adjustment, but you can change color and /or saturation locally…

Choose a color in the Color Picker, if saturation is set to -100 it will replace the original color. If saturation is higher it will blend the two. Play with Saturation and Exposure to get what you want.