Everything is too close to the background. Being that close, the 'cones of light' from your background lights don't have time to spread. Move the background lights at least three or four feet to the sides (if possible) and toward the camera position. I generally set one background light on each side of the background, pointed so that the lights spreads across the background paper and overlaps. Then move the model at least five or six feet farther from the background. For a pure white background, have about three stops more light on the background than on the model.
In the attached shot, the model was about six feet from the background and the background lights about half way between her and the background and a bit to the side of the paper. Main light was a softbox slightly higher than the models face. Since the background was white fabric instead of paper, I allowed just enough exposure to let some of the folds show (more visible on the print than on this small image).
Distinctive Images