Is it a direct link? As in <a href = "http://www.example.com/"> in the body of your page? Most facebook links don't show up in g### at all because they go via the "leaving facebook"* page-- the one you see in logs as facebook.com/l.php?u=your-page-here.
* I just checked. The page has a noindex meta:
meta name="robots" content="noodp, noydir, noindex"
But I don't find a "nofollow" anywhere.