i mean. . .goto setting on ur phone>>>application manager>>all application>>camera>>clear cache or clear data. . .also clear gallery cache and data if the first one didnt fix it
I think you should trouble shoot it and see whether it's the software or hardware first!
By the way does it open,I mean is the flashlight onning ?
Hold down the volume up button whilst the phone is off to go to test mode and Scheck from there whether your it's working there!
You can also Google mtk engineering app and download it and use it to troubleshoot!