I've changed Glass + Digitizer many times and I got a White Screen.
First time it happened to me, I replaced LCD for a new one (20$ eBay LCD) and solved the problem.
Now, occasionally, screen can go white again and a simple tap on power off and then on again solves the problem temporarily (or a reset with 10 seconds POWER + HOME).
For what I've read in many posts, it's almost certain that there's an hardware issue in the LCD or the main board connectors / ribbons when you got a white screen.
Of course, everybody is always hoping (like me) to solve occasional white screen without having to replace LCD.