If this is a professional event for you, I’d say, ditch the guy until you can see him on your own time, much later (like another day - when maybe you two will have more time to get all cuddly). You have two things going at once, and it’s bound to cause you some sort of conflict.
Like what you see on those situation comedies on TV where everything seems to go wrong. It’s funny there, but not in real life.

As far as makeup, you should probably wear a base, if you need to and put on your makeup conservatively, no eye shadow or anything but natural colors. Wear a suit, or, if female, a dress (nothing low cut) with long jacket. No dangling earrings or obvious jewelry.
References :
On a science faculty in high school and undergraduate college. Participated in award ceremonies.