MacBook Pro strange white screen upon rebooting mouse and trackpad not working
The first thing I would do is reset the NVRAM.

Resetting the NVRAM

Your Mac uses Non-Volatile Random-Access Memory (NVRAM). To reset the NVRAM on your MacBook Pro model follow these steps:


Fully shut down your machine. 
Press the power button and then immediately press the commandoptionpr keys. 
Keep these keys pressed down for at least 20 seconds!
Let go of the keys and let your Mac reboot normally.


Note:**Assuming this resolves the issue and you can log back in fine, you ***may* need to readjust some of your system preferences (e.g. speaker volume, screen resolution, startup disk selection, time zone information, etc).

If you still have problems after doing this, let me know.