smudges or dark marks behind the iMac screen

[MelonBlue]

I have an iMac (27-inch, Late 2012) and i have noticed these smudges or dark marks on the screen. After a closer look, it's clear that these smudges are actually behind the screen itself so the mouse cursor looks like its above the smudge. So is there a method or a solution I could try at home because I'm currently outside the US and there aren't any close Apple stores.
these are the pics:
http://imgur.com/erwoWbF,RVn7Q47#0
http://imgur.com/erwoWbF,RVn7Q47#1

 

[ZMacintosh]

unfortunately not. that looks like screen contamination from the either the panel or the lighting of the panel, they definitely need to be replaced.