What should I do if my back camera on my iPhone 5 isn't working?

I dropped my phone on the back and the back camera has been acting weird ever since. It happened last month but it would still work if I pushed on the top of my phone and I would be able to take pictures but they would be a little blurry but ever since today the back camera won't work at all. When I open my camera app, Instagram, snapchat it goes right to the front facing side of the camera and won't even let me change it to face the back camera. I tried resetting my phone, deleting and installing the app, pushed on my phone but nothing is working. Should I take it to the store or is there something I can do from home?

How to make an app forget my details for good?

So basically, I've got this app in my iPhone 5c and the only way to use it is by "logging in with Facebook" which I did.
This was two weeks ago.
Now I need to use this app with another Facebook account.
I've signed in with the new account onto Facebook (the app) and messenger as well. Still when I "log in with Facebook" it logs in as the old account.
I have even tried to delete the app and install it again and still the same.
Any ideas?