The 'Chelsea Smile' Effect.
This is one of my favourite pieces that I have done.
I used 'Mouldlife: Sculpt Gel' to create the sliced effect on the face and shot I series of four 'stop motion like' photos where the cut makes its way across the face, above, being the last photo in the series.
I used veinal blood (also from Mouldlife) to drip and smudge around the face. I used a larger amoun of blood in the cut to give it depth and make the whole look seem more realistic.
One of the great things about making gory cuts on a face is that, if at any point you make a mino mistake, you can always blend it and cover it with the blood, which can be a real life saver at times!