I'm looking for a way to add blood to an actors face in post (i didn't have time when originally shooting). This may require after effects or something similar but i thought i would see if i could keep the effect in Final Cut Pro first.
You'd have far better luck using After Effects or Motion...because you will have to do a lot of tracking and keyframing. And it won't look realistic, because of the shadows you need to add, the reflections of lights, the need for it to lock solidly to the actors face, which will be moving.
This will take a LONG TIME. A heck of a lot longer than dabbing fake blood to an actors face when shooting. And it won't look as good. Even blood added in post on major motion pictures is easy to spot.
And they have hundreds of man hours and deep pockets.