Is something wrong with my TV?

I have a Hitachi 55 inch rear projection TV and it has developed a blue haze that covers part of the screen. It seems that the blue spot occasionally changes and moves. When white is displayed on the area of the haze, the haze cannot be seen. I have occasionally left the tv all night by accident (falling asleep while watching it) could this have caused the blue haze? Are there any solutions to this problem?