How I made the jaw:
I sculpted it with plasteline on a plaster mould of my face, adding resin teeth that I bought on Amazon.
I removed the teeth, removed it from the plaster face, and made a cast of it with silicone. I then mixed up trowel-on 60 and painted it into the silicone mould.
Once that had set and was removed, I coated it with two layers of sculpt gel (a pink gum colour, and a red flesh colour), then painted it with Skin Illustrator.
On the day of the application I made a layer of fake skin with Sculpt Gel, and adhered the jaw piece underneath the skin layers.