Generally Hardware either works or it doesn't - unless you have a pinched or twisted iSight Camera Cable it would not suddenly cure itself of a problem. If you had such a problem it would appear/disappear almost every time, or every other time, you opened the lid on the MBP.
This is not a software fixit forum - there are other better places for that. Apple Discussions for your particular MBP, OS, App or device would be one of them.
Often when apps act strange (FaceTime?) the .plsit file is corrupt. Go to ~User/Library/Preferences and find any and all files with FaceTime in the name. Delete them, log our or reboot your laptop.
If that works remember it. If it doesn't you may have a hardware problem.
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