I’m guessing that the blue rose, which also appears on one of the publicly released photos, is somehow important for the plot. It also makes for a very memorable and striking image. And the little blood drop in the bottom is a subtle but smart reference to the topic of the movie.
All that said, this movie will probably be sold on the “Lyndsay Lohan as a stripper” hook. So I’m guessing the poster, which doesn’t even hint at that, won’t matter much. It is still a nice poster tough.