I saw on TV's Extreme Makeover that if a person has really dark eye circles, they inject some fat under the skin. I guess the fat hides the blood and whatever else is dark under there. The lady they did that to really looked a LOT better (that and the other 69 things they did to her, lol)
But the doesn't seem like a healthy thing to do. I guess you do what you can do, cleaning up the body, and after that learn to live with it, perhaps involving some concealer as well.