You can use the Show Face Outlines button on the View mode toolbar to show or hide face outlines in your images. You can also use the keyboard shortcut SHIFT + B to toggle face outlines.
The state of face outlines does not affect the Face Detection pane, so you can still see and label faces in the pane with face outlines hidden.
The state of face outlines does not affect the Face Detection pane, so you can still see and label faces in the pane with face outlines hidden.