I Updated Facebook and now It Won't Work
Edit: this appears to be a problem that Facebook recognize. It's a problem with the Facebook app, as well as not a generalised Play Store problem.
This is what worked for me at the very least.
- Settings > Apps > All > Google Play Shop, Clear information as well as Clear cache
- Settings > Applications > All > Google Play Services > Manage area, Clear all data and Clear cache
It doesn't injured if you reactivate your phone prior to you attempt upgrading facebook once again. As well as, the install was SLOW. Just at least 4-5 mins. But, it did work. If not attempt to uninstall it, or simply await a solution.