Facebook app won't re-install on iPhone?

I un-installed my Facebook app from my iPhone because it wouldn't update. I additionally deleted it off iTunes then re-downloaded it onto iTunes. The problem is that when I'm on the app sections off my phone on iTunes, I click install on the app then apply changes, but it doesn't want to install at all. What do I do?

Try installing directly from the iPhone app store. Or try re-booting your device. I once tried to install Modern Combat 3, and I had to reboot to install it.