I was repairing my iPhone 5S screen when I found out the new screen I had been sent did not come with a metal back plate for the LCD. I tried to take off the one from the original screen, but one of the screws was stripped and I couldn't take it off. Is it ok to use my iPhone without the metal plate behind the LCD, or do I need to wait until I can get a new metal plate?
The iPhone is not user serviceable and Apple doesn't sell parts so you won't find much help here and now that you have opened the phone you won't get any from Apple.
I do believe the plate is required but to check further you should go to the forums on http://www.ifixit.com
The plate is probably radio shielding to prevent interference. The tolerances on these device is so strict that leaving parts out may make it fail to align or even work at all. I'd leave it alone until you can get a replacement.
LCD metal plate
