I seem to have figured it out on my own, although it's more a workaround. Simplify3D has what is called "vase mode" which allows me to force a 0% infill. If I print the entire 3D head in this mode, then I can use a pair of scissors afterwards to cut out the section of the head I want for the "mask." Seems to work pretty well, but unfortunately it's time consuming because I have to print the entire head instead of just the section of the face I want. Perhaps I'll find something faster in the future.