Question [Q] Quick help please!!!

I wanted to install 4.4 Settings apk, so I copied it to system\apps. Restarted phone, and now settings are gone! so I had a copy of the original 4.3 settings app by sony, and even when I copied it back still no settings. What should I do?
I need help really quickly!!!
Sony Xperia E1 but the settings app must be the same on every device.