1
Look at the function keys (F1 - F12) on your keyboard, if one of them has a camera icon, press that key or Fn + that key to unlock the webcam.
2
If that was not the problem, look at the camera lens above your screen, is there a small privacy slider that needs to be opened to access the webcam?
3
Check the actual webcam lens above your screen, it may need to be cleaned.
4
Open the Settings Ap.
Go to Bluetooth and Devices - Camera.
Click the Integrated Camera section.
In there, are sliders to adjust the Brightness, Contrast, Sharpness and Saturation on your webcam, try using those sliders to adjust the image created by your webcam.