BB Storm :: 9520 Broken Screen, Glass NOT Cracked?

Been a Blackberry user since March last year, although I seem to have struck lucky with the particular blackberry I've got - my Storm2 9520 has been a catalogue of problems since the start.Anyway, last night I dropped the phone in my room, and the screen broke. Now, all that can be seen is a bizarre, inky pattern onscreen, obscuring everything bar the very bottom of the view. However, the glass screen itself is undamaged. Whenever I've looked on the internet for fixes, nearly all of them seem to deal with cracked glass screens, but my screen is undamaged - the display and what's showing up onscreen is the problem. Now, I'm not very tech-savvy, so here's my questions for you all:

1) what is the nature of this problem, i.e.. what is actually broken?

2) does my Vodafone warranty likely cover this? I've already sent the phone off once to be fixed, when the screen was not working properly and wouldn't respond properly to my button presses.

3) If no to 2), how easy would it be to affect a fix myself? Would it simply be a case of buying a new screen part and fitting it?