Quote - So i really think it's a trans problem.

One thing to try is to connect the transmap to the Specular_Value input and set the Transparency_Falloff to 0.0 (many older MAT poses leave the Falloff at it's default of 0.6).

If that doesn't cure it, you might try adjusting the Shadow Bias on any lights you have castinjg shadows (given that skull cap like parts are usually very close to the surface of the head).