Welcome to the forum.
Have you tried pulling your battery out of your device for a minute and then placing back in? This sometimes corrects the issue. In this case I would delete the application and try reinstalling. If that doesn't work, I would roll back to the previous version.
You can download a previous version of FaceBook from this link http://theiexplorers.com/OTA/#Facebook
(Visit the link from your browser on your device)