I don't think there is an option to 'un-hide' an embedded layer.
But then I don't seem to have this option to hide them either - but that just be my Work Environment.
But no matter.
Open the drawing settings then open the "Drawings own layers" and turn on/off whatever layer you want.
Barry.
One of the forum moderators.
Versions 6.5 to 27
i7-10700 @ 2.9Ghz, 32GB ram, GeForce RTX 2060 (6GB), Windows 10
Lenovo Thinkpad - i7-1270P 2.20 GHz, 32GB RAM, Nvidia T550, Windows 11