When you make or receive a call on Skype, you don't have to display your camera feed. The application gives you the option to disable your webcam and communicate solely through voice chat. There's no option to block out only your face, however.

Turn off the Camera Feed

If the call is already initiated, mouse over the call window and then select the camera icon from the toolbar to turn off your video feed. If you're placing or accepting a voice call, select the phone icon and not the camera icon.

Disable the Webcam Driver

You can temporarily disable the driver for your webcam. If the webcam is inactive, Skype won't give you the option to make or accept video calls. Press "Windows-Q" to open the Apps screen. Type "devmgmt.msc" (without quotes) into the search box and then press "Enter." Double-click "Imaging Devices," and then right-click your webcam and select "Disable" from the context menu. To re-enable your webcam at any point, perform the same steps but select "Enable" from the menu instead.