Mapping SSS

I’m trying to achieve the effect of bone blocking out SSS.

Is there a way of painting maps to control this? If I add a matte to the Overall color slot the result doesn’t reveal the diffuse color.

Any help would be appreciated cheers.

I believe you need to paint the scatter color (from red/orange to black). You could use a composite node to multiply a grey scale image over your red/orange and put that in the scatter color.