Goby jaw injury?

[QuiGonJay]

Today I noticed my watchman goby's left jaw area was swollen and discolored (maybe red not sure). He's behaving fine and eating but I'm worried. Honestly, it looks like something punched him in the face. Only tank mates are striped blenny and blue legged and red legged hermits and a rock urchin. All there for well over 6 months. Will try to post picture but app is misbehaving. Any advice appreciated.

 

[QuiGonJay]

 

[fishy boy]

It could be and infection

 

[fishy boy]

Or maybe he ran into the urchin I don't know

 

[QuiGonJay]

Never had to treat a fish. Should I try to remove to quarantine to treat or see if it heals on its own?