So you don't find her attractive at all without makeup? Then you should probably move on. If you can't get over that she probably only wears makeup like that when she goes out to the bar and not anywhere else. Then you will always have issues with her appearance. If you have gone on two dates and she hasn't worn makeup, that is a sign that she likes that look compared to wearing and although you find the makeup her hotter. You don't get that all the time. No nice way to tell her that. It will hurt her feelings if you tell her she looks better with makeup because that will mean she looks ugly without it. You could try and compliment her on how great she looked that night and tell her you would like to go out and get dressed up like that, but sounds like it won't happen often. Good Luck
I agree with everyone on here, if you don't like the girl for her looks, then don't date her. Plus in a relationship it's all about personality not looks. If you're most interested in looks then go for one night stands lol.