Welcome to Discussions, John Ben.
The fall may have damaged some of your hardware, but you can try some troubleshooting to see if the problem might be something you can fix.
(1) Restart Mac and then try your camera again.
If the problem remains, use all relevant suggestions in http://support.apple.com/kb/HT2090
(Apple has changed the built-in camera's name on newer Macs from "iSight" to "FaceTime" and then to "FaceTime HD." Regardless of the name of your Mac's built-in camera, the same info and troubleshooting applies.)
Be sure to test more than one camera app in more than one user account. Do NOT use the "Guest" account for this test. If you do not have more than one user account for the testing, create a new one now. (A "Standard" account is all you need for testing.)
If your problem is with more than one Apple App in more than one user account, try the MBP reset suggested in the Troubleshooting article. The "reset" for your model sometimes restores normal camera function.
(2) If your trouble is ONLY with connected apps like Skype in every user account you test, shut down everything. Restart your modem, router (if you use one), and Mac in order. Let each item complete its self-test before starting the next. Sometimes restarting your Internet connection improves performance.
If you normally connect via Wi-Fi, try connecting via ethernet cable. If wired connections work, you will need to troubleshoot your Wi-Fi further.
(3) If your troubleshooting proves that yours is a Skype-specific problem, (your ONLY camera problem is when testing Skype in more than one user account,) update to the latest Skype version compatible with your Mac OS and test again. If the Skype problem remains, Skype's comprehensive support system should best be able to help you use their product with your system.
You can search or post for help with your problem in Skype's dedicated Skype Discussions for Mac. The Skype users who post there may have already solved your problem.
If nothing else works to fix your Skype, you can even sign in and ask for email help directly from Skype's Technical Support people.
(4) If your camera problem also occurs with non-connected apps like iMovie and QuickTimeX Player, you may need to have your Mac professionally serviced.
Unless you have a current backup, make one now.
Then use Apple's final "Troubleshooting" suggestion:
"... contact Apple or an Apple-Authorized Service Provider for service."
(5) If you want to try one more thing on your own before seeking professional help, use your Mac's Disk Utility to repair permissions.
Then download and apply the latest Combo Update for your OS. Currently, the latest ML Combo is http://support.apple.com/kb/DL1640
Repair permissions again immediately following the system restart that completes the 10.8.3 Combo update.
Properly applying the latest Combo version of updates can sometimes correct software problems, but, if your trouble is really a hardware problem, there are no user serviceable parts of the camera. Your AASP can fix hardware issues.
Message was edited by: EZ Jim
Mac OSX 10.8.3
