Thanks for the image of the movement. Yes, it does look like a little piece of lint near the 11:00 marker. And yes, once you remove the bezel by prying at the small separation, you should be able to blow it off. The trickiest part will be getting bezel back on. It's easy to push the crystal out. You need to line things up well before pressing along the bezel, without touching much of the crystal. That said, with an 18s/Ns, it's the easiest you'll get. That's a nice coin-edge bezel, so be gentle. Good luck.