There are a few ways to change hair color in Photoshop. The first way is to use the Hue/Saturation tool. To change the color of a hair, click on the hue wheel and then drag the slider to the desired color. The second way is to use the Color tool. To change the color of a hair, click on the color wheel and then drag the slider to the desired color. The third way is to use a gradient tool. To change the color of a hair, click on one of the gradient tools and then drag it up or down to create a desired effect.