teeth whitening gum shield

Color to black. Paint over the mistake to hide the effects of the adjustment layer, then press X again to switch back to white and continue painting.

For some areas, you may also find it easier to paint with a lower opacity brush.

You'll find the Opacity option in the Options Bar at the top of the screen. A low opacity of around 20% is sometimes helpful to avoid over brightening teeth in the darker corners of the mouth: Continue painting over the teeth until you've whitened and brightened them all.

I'll zoom back out of my photo, and we can see that the man's teeth are now just as white as the woman's teeth: Keep in mind that no matter what the toothpaste companies want us to believe, our teeth are not supposed to be pure white.