Can this LCD be repaired?

The screen of my 20" iMac has what looks like a crack mark on the top left corner (See image) but the glass on the outside has no crack. The screen is generally gray, white and and black but I can partially see the desktop behind the white parts. It also seem to get slightly better (i.e. I can see more of the desktop) after the computer has been on for an hour os so (see attached image).

I am still using the computer via a secondary monitor.

What is wrong with the lcd?