Great result man!
As for the bumps I think they are due to the hair on the actual guy.
Should be a bit more than just
stubbles.It's not only in the back,but
everywhere where there is supposed to be hair.
And when cleaning up the scan you have to find a solution for that area.
Moreover many people tend to use 3D hair on top of it and then it might
even look slightly more real.
The waxiness is indeed something you can see in many renders all over
the web.That's probably why there are so many threads about this topic.
From my point of view subsurfscattering is really over-estimated,especially
in the movie and video-game fandom/fan communities.Their heroes have it,
so they have to have it,too.And thus there are thousands of glowing blobs
to be seen on every cg forum.SSS and three point lighting,hooray!
Just my opinion.