So my question is, after I have created a complex face with a great deal of polys (1 million)in Zbrush, is it still possible for me to take it back into Max and create a UV map for this, with all of those polys represented in the UV map? I guess I don’t really know anything about UV mapping, and here I went and sculpted a very detailed model, and now I don’t know if I have gone too far to UV map it. Can anybody help out a nub like me? Thanks in advance.
In your lower sub-d level
Tool > Texture > GUV tiles 
You can also go to level 1, export it as an OBJ, UV it, then import the new version back to replace the current level 1. So long as your point count/order is not changed anywhere in the other app, you’ll be good to go with the new UV’s.