My thoughts, if you're playing an 'ugly' character chosen from a faceclaim to simply go against the grain, you're doing it for the wrong reasons. 

Play the character you want to play. The one that's running around in your brain begging you to bring them to life in a story - whether they're a trope, beautiful, ugly, an alien, a microbe idk. Play the character that makes your soul sing, and write them [i]well[/i].