The eyelashes actually kinda have a story behind them.
Mysa is from a planet called Naltor, see, where everyone can see the future to various degrees. Mysa was born with out this ability, which was difficult since her sister Nura, fellow Legionnaire Dream Girl, is a highly gifted seer. So Mysa decided she wasn't going to sit around pitying herself for being a cripple, and went to the Sorcerer's World to learn magic. As she got better and better, her appearance started to change, resulting in the antennae-like eyelashes. So yeah, apparently getting really good at D&D style magic makes you look weird.
Yeah, I dunno, it's the future.