Yeah but you can change the lightning mode to “Surface Translucency Volume”, then you got roughness and metallic 
I just did a basic glass material out of the head till it looked somewhat realistic, so you might wanna change it.
Basically I set the metallic to 1 to don’t have too much colors and used a fresnel for opacity and roughness.
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You might wanna add refraction then, but since the refraction index of glass is nearly 1 (so nearly same as air) I spared it here.
You can then use normals in the material and the fresnel to put in some imperfections. And you might wanna multiply the opacity with a parameter before the clamp to get more control.
EDIT: base reflection of 0.05 looks better than 0, so you might wanna change that directly