How severe is this infection/cyst based on the X-ray?

X-ray: https://imgur.com/a/GGuqXmV

Background: I had this X-ray taken of an area right above a very small amount of pus that leaks from my front tooth. I used to have a painful abscess there that leaked way more pus, but I had a root canal done followed by antibiotics. Since then, the abscess has largely gone away, and all that's left is an almost invisible, tiny little lump maybe two millimeters across, where a much smaller amount of pus apparently still leaks out, but I never even notice it now.

Is the dark spot more likely indicative of just the infection, or a mass like a cyst that is causing the infection? And does it look really bad in this X-ray, or how severe is it exactly? Thanks.