Most photographers will tell you that you MUST hire a makeup artist, and if do you choose to for our shoot, I have a few I work with. For me, I say: know thyself. I personally need a hair and makeup artist for headshots. I can make myself look all right for an audition or night out, but when it comes to the skill it takes to apply makeup for myself that is that perfectly natural and effortlessly beautiful look you want for a headshot, I just don't trust myself like I do a professional. That being said, there are a few folks in my portfolio who did their makeup on their own and 100% rocked it. I'd just say be realistic and do that at your own risk--extensive retouches to fix uneven or sloppy makeup may cost more, or even just ruin the photos and make them look less natural from all the retouching. And with the time, energy, and money you are investing in this, you do not want that. So again: know thyself! When in doubt, hire a professional. It's worth it.