Cameras are not really uninstallable like that. They are also not listed in the "Settings" usually. Except in "Apps".
First try restarting (turn off and back on) the phone. This may resolve the problem.
If that did not do it, did you try looking in the "Apps", then "All" in "Settings" and see if the camera is listed? Then you can also tap and hold the background of any home screen and in the popup window that shows you should get icons, widgets, etc., that can be added to the home screens. Did you look for the camera icon there?
If the camera is in those areas, but won't work for you, try starting up the phone in "Safe Mode" and see if the camera will work. If it does, then you have a virus, malware, bad app, etc., on the phone that...