I Updated Facebook and now It Won't Open
Edit: this appears to be a problem that Facebook recognize. It's an issue with the Facebook app, and also not a generalised Play Store concern.
This is what helped me at least.
- Settings > Applications > All > Google Play Shop, Clear data and also Clear cache
- Settings > Apps > All > Google Play Services > Manage area, Clear all information and also Clear cache
It does not hurt if you reactivate your phone before you try upgrading facebook again. As well as, the mount was SLOW. Just at the very least 4-5 minutes. Yet, it did job. Otherwise attempt to uninstall it, or merely wait for a repair.