No Display After Repairs

Fixed the cracked screen on my iPhone 3GS, but got a big piece of dust under the screen. When I opened it back up, it was still powered up and one of the cables for the digitizer got disconnected. Now I get no display. If I press the power button, I get a few seconds of the screen flashing white, then back to no display. iTunes recognizes the phone, and syncs with it. Upon eject, the screen lights white briefly then goes black. When I call the phone, it rings and the screen lights up white, once again briefly. Basically my phone works, except for the display. I've restored numerous times with no luck. I've let the battery drain, and reconnected it to iTunes to no avail. Any advice from the community would be greatly appreciated, thanks.