Jason,
Does the face stay parallel to the camera the whole time or does head turn through the shot? If the head does not turn, I would track with translation and rotation only in Mocha. If the head is turning, then you would want to track with all the parameters and use the corner pin effect to place the wound on the face.
One thing I forgot the mention, is that when you paste the data to a null, you want to make sure to turn off the keyframes for the anchor point and scale (turn off scale as long as the face stays the same distance from the camera). Also, make sure that you don't change the inpoint of the clip in Mocha AE. I have found that I get strange results in AE if I do.
I posted a file a while back for someone that was having trouble...here it is. The is one of Andrew Kramer's tutorials. It includes the footage, the Mocha AE Project file, and the AE project file. You can take a look at it to see how I used position data from Mocha AE in AE. I think it might help. Please let me know if you need anymore help.
http://www.cmimagery.com/docs/Mocha_AE_Setext.zip
KMS
love
