I have had this problem many times. Letting it sit by itself for a few days isn't an option. People drop off their phone to get fixed and they expect it to be returned 30 mins later (give or take). I think it has something to do with where the LCD flex attaches to the actual LCD. I've tried everything short of replacing this flex to correct this problem. I've completely disassembled the LCDs of the 5 series phones and this seems to be the most vulnerable spot. I haven't dug quite deep enough to learn whether there is a way to re-attach the LCD flex to the LCD for just the average amateur repairman but I have a feeling that will be pretty much the only solution. And that will require separating the glass from the LCD and basically doing a complete glass only screen replacement and that is a tedious and time consuming task. Especially if you wind up having to replace the backlight too. I know I haven't been much help but maybe this will steer somebody in the right direction so I can learn exactly what the problem is too. I can't take many more defects like this myself.