Blank white screen at log in.

I added my mobile number to my account and had to change my password. It then said I had successfully authenticated and password was successfully changed. But following a 24 hour hold for my security, I can now log in but all I am getting in my fb app and though my browser is a blank white screen and the single option available it to log out. I can't even contact fb to ask for help because the screen does absolutely nothing but give me an option to log out. Can anyone help?