If you follow the repair guides on ifixit.com for you device, you can run a quick little test. Seeing as you damaged the front camera, I wonder if there may be a short causing it to reboot. You can order ifixit’s screen replacement kit that’ll have the tools you’ll need to perform the repairs. I would first test it with the front camera assembly disconnected. If that’s the case, just order a replacement. I recommend Mobile Sentrix or Mobile Defenders.