If you dented the screen on an LCD you are lucky it didn't break the glass. Dents in the protective layer will cost you about the same as the TV costs new. The outer screen consists of a non-reflective layer that is part of the panel itself. You should consider youself lucky the glass didn't crack.
The LCD panel is rather thin glass layers on top of one another, and any impact is usually enough to shatter the inner and outer glass
A new panel will run you $2000 or so, if it is watchable still then you could put it in another room, or sell it somewhere for parts.
No manufacturer will cover a cracked panel, so the warranty is of no help either.
Sorry! Please don't shoot the messenger