Yesterday, due to poor breadboarding practices, I had a very new Panasonic 18650 (labeled with NCR18650PF, MH12210, and "Do not short circuit") shorted for several seconds. I noticed because it was smoking—it melted some wire insulation. I don't think the casing got hot and it seems completely undamaged. Today it shows the same voltage it did yesterday (4.1V). Have I made this battery any more dangerous than it already was? I don't care if it's life has been shortened; I just want to know if it is time to recycle it instead of having nontrivially increased the risk of it exploding or catching on fire. (I couldn't find a trustworthy answer about this with Google.)
No, not dangerous.
If it didn’t get hot, nothing bad happened, as the wire melting prevented from too much current flow, and it probably happened very quickly, so not much damage has been done.
You probably lost bit of cycle life, but nothing noticeable.
If it was a pouch cell however, not a cylindrical cell like an 18650, then yes, I would’ve thrown it away.
Due to how pouch cells(LiPo) are built, they generate much more gases under bad conditions, compared to cylindrical cells, and are much more dangerous.
TLDR: Keep it. Don’t try to short it next time. 
Awesome. Thanks for the response. I will figure out how to put an obstacle in the way of me shorting it again. Partly it was because the flexible part of the grounding wire for my oscilloscope probe is only 4" (making me keep parts closer together than I would prefer).