What kind of makeup should be worn for pageant headshot photos?

Something neutral but standard pretty.

Understand the lighting for the head shots, you don't want too much contour or shimmery highlight.

For me, this is a full face of foundation, light contour, minimal highlight, neutral shimmery shadow, a darker shadow on the outer corner and crease, some light eyeliner, and a few coats of mascara. I don't like false eyelashes because they hit my glasses lenses, and I have long enough lashes they look fake anyway. Finish it off with a nice lipcolor. Personally, I like bold lips, but go with something that is more you.

Your hair should be done up, and you should be wearing something formal. I only say this because the only pageant head shots I have seen are of the winners, who are wearing a big gown with their crown and matching jewelry. If you have a crown or other trophy, and it was from something recent, wear it.

I would try to find a photographer who has done pageant head shots before, that way they can help guide you through what to do so you get good pictures.