Hey everyone, I was chekin' out videos on youtube about this problem and I found a comment what worked for me:
"Radko Vattai 2 months ago
HEY, So... I just recently tried this. There's a whole thread on apple forums about this problem. I had this problem after updating to the new ios7 so annoying. anyways the trick I did for now my back side camera is working because all I did was PUSH DOWN REALLY HARD on the top right corner of the phone where the camera is. I was pushing with my thumbs and fingers on the backside camera and then I restarted it with the home and lock button and when it turned on it works.... I don't know how long it'll last but try it out."
Hope it works for you guys as well,
Cheers!