If Danny O’Conner was smart he’d accept that he lost the special election, and devote his remaining resources to trying to win the general election. Sadly, it’s highly unlikely he’ll win the seat in November, because, if he couldn’t flip it in a august special election with low Republican turnout it’s highly unlikely he’ll flip it in a high turnout general election when more Republicans show up.
This wasn't a low turnout special. The turnout was barely lower than 2014.
Indeed it was, and that doesn't bode well for O'Connor, since turnout in Franklin was nearly maxed out while rural, largely Republican turnout remained low.
Was turnout in Franklin 100%? No. Then it wasn't maxed out. There's no reason to expect Republican turnout to rise more than Democratic in November.
Reversion to the mean is a good reason to expect turnout in November to follow more "normal" patterns (even if still probably Democratic-favorable) than many of the specials have.