I found this a beautiful picture, everything ties in perfectly. It a eye catching, piece of work. The dark purple around her makes her have a breathtaking aura, like she playing with fire. A great impact, and a interesting technique of the background.
But my advise for this contest entry, and not trying to sounding rude. But use Photoshop, and write your name with the text(or tablet) on a new layer. After, shrink it so it doesn't ruin the picture but it still showing it's your work. Instead of having marks docked off with having the watermark on there. It's just a thought. Good luck in it.
This is a wonderful picture of a dark Lena. One of the only things I would advise you on would be her leg. It seems a little large in proportion to her delicate torso. Also, the blobs seem a little pix-elated in comparison to the rest of the black, swirling smoke that is wafting off of her. Are you going for that look? The things that I think are the most spectacular are her dark eyes. They seem to jump out of the picture and captivate every spectator. I love the casual way that her dress is slightly uneven/ruffled. It gives her a 'bad girl' look that I would expect in an evil girl. In the end, it's an excellent image that has a great chance of winning. I could see that on bill boards!