It sounds like the screen connection came loose, although I'm extremely surprised that it didn't crack. Your only options are to replace the phone or disassemble it yourself and reconnect the screen. Are you up for that?
The screen failed on my Droid X and needed to be replaced. Out of warranty and no insurance, so I got a quote from a local phone repair shop. $100 to replace the screen or $65 for the part and I could install it myself. I bought a new screen on eBay for $22 including shipping and the tools needed to do the work. (2 miniature torx screwdrivers and a plastic pry tool)
I found a you tube video with step-by-step instructions on how to do the screen swap and it all worked out fine. I used to work on laptops and I've always been good with tools, but that mostly just gave me the confidence to go ahead and try it.
Find a video for your phone and make your own assessment. Around here,(Portland), Fry's electronics sells the miniature torx screwdrivers and plastic pry tools or find an online source.
If you are going to do it yourself you want to verify before you start that you also have the digitizer attached to the replacement screen because without it you will have to carefully pry the digitizer off the old screen.