add "shy" effect onG3 face with shell

hello artists
I want my G3 charactar can have a effect on face like "shame","shy"or"blusher"
I have heard that there is a method called "shell" in daz, and it won't modify the original MAT of G3, can anyone help to tell some steps or details, thank you.
Comments
It's called GeoShell, you can find it in menu Create-> New Geometry Shell.
It will create a sort of duplicate of the char or prop you selected. It will appear in the Scene listing like a normal wearable. The UV will be identical to the base figure and you can apply any sort of shader or texture on it.
You can also decide which part of it will be visible using Surfaces tab and its internal options in Parameters->Shell.
A geometry shell can actually have a different UV than the base.
thank you ! I will try !