Richard, for me this is one of the most difficult PP problems to solve because it is difficult to darken the highlight on her chin and retain some modelling of the curve. However try this:
1. Select the area and copy it.
2. paste it back as a layer.
3. Clone some texture back from the middle of her cheek onto the layer at about a 40% - 50% opacity.
4. Add a Layer Mask and then use the gradient tool from left to right to vary the opacity of the cloned texture to get some shape back into the chin. You will need to experiment with the start and finish point to find the best compromise.
5. If necessary, alter the overall layer opacity to get the best match with the rest of the face.
6. Flatten the image and clone at low opacity to get rid of any edges.
7. Dodge and Burn as needed to tidy up.
That should produce something like the image below in which I have also used the Highlight/Shadows tool to selectively pull back some detail in the broach around her neck and to better balance the peripheral highlights with the area around her eyes.
That would be my approach. Hope it is of some help.
P.S. I still like the High Key approach.