incase if anyone's interested, MASTER DUNCAN has replied to this on another forum:
DUNCAN:
"Make the animated face into nCloth, then make input mesh attract around 1.2 and paint the inputAttract per vertex black where you want it to melt. You could instead use a texture map if you wished to animate the texture.
You probably also should do "Rest Shape: Connect Input Mesh to Rest Shape". The bend and stretch resistance will now use the animated face instead of the shape at the first frame. The input mesh attract always uses the current input mesh state, but as you lower the input mesh attract you will lose some of the facial animation. By keeping stretch and bend relatively high you can allow the face to deform but still keep the facial animation.
Depending on your animation you might also wish to enable the volume conserving pressure method, which would attempt to preserve the volume of the head. As it melts you may wish to then animate the stretch/compression resistance lowering so it can flow like honey."
Duncan