Seeing some unusual things going on. Uncheck reflection_light_mult. That's a  hack that's contributing nothing, probably to the shader's detriment, especially with GI.

It's also unusual that a bump, displacement, AND normal is going on. There's no math subtract modifying the displacement.

The shader looks like a scatter blinn setup, something that bagginsbill came up with and led to EZSkin.

Also looks a bit like it has both an image map mask AND a procedural mask modifying the specular. And both specular inputs are being used.

The scale value on the scatter is REALLY low, I'd be surprised if you weren't having blue tinting artifacts near areas of mesh in close proximity such as lips, nostrils etc. That's a very translucent setting.

Kind of a hodgepodge.

I'm far from a shader guru but even I can see some things wrong here... just from looking at various scatter blinn set ups and experimenting with them over the years. You might consider changing your set up to a straight EZSkin formula.

I leave it to folks more knowledgeable, just doesn't look like something I would use.