How to fix my iPhone 4s Front camera?

[Cole]

I recently got my screen replaced because it cracked, i dont know if that is it but.... and what it does is when I open my camera app up, it automatically goes to the back camera and if I try to switch it, it just freezes... also on snapchat/instagram there is no camera flip button, please help!

[keerok]

Try reinstalling the app. If that does not work, return the camera to the service center and complain.