You have a hairbrush, hair dryer, and hair dye! Click a color and use WASD to move the hair dye to where you want, and then drag it to begin dying. Use the tools in the bottom left (and right) to adjust the face cam transparency and the pen width. Have fun doing your hair!
I apologize for my poor drawing skills. UPDATE: Now what does "input update" mean? Instead of needing to click the up and down buttons several times, you can type in inputs! Well, now, if you look in the same box as the unnatural hair dye colors, (the bottom right corner) you will see two new buttons: Input Dye Width and Input Transparency. Click the dye width one and type in a number that you want you dye width to be. The transparency (100= face cam off, 0= face cam on) button will ask you to put in a number one hundred or less. Type in numbers to adjust your dye width and your face cam transparency!