You need to add specular color. so you need to mix with glossy material, pity that Lux use Schlick model for glossy materials that behaves not good for low exponent values as Phong model does.
You need low exponent values because high or medium values makes skin look plastic.
Maybe Torrance model (metal material) can behave better than Schlick for low values, I have not experimented yet

Stupidity also evolves!