Gem Tang - end of mouth is white??

[JonF]

Any thoughts on whether this is just the coloration on the end of his "beak" or some type of infection? Has been sort of like this since i got him about a year ago. End of beak is really not white from the other side of his face. Not puffy/cottony at all. Just white. Think its ok? He's been in quarantine for about 6 weeks now with copper.

 

[JonF]

By the way, his dorsal fin is recovering from an aggressive large tang that's been removed from the system - he's coming along very well that way - just looking for advice about whether the end of his beak is a problem. Thank you!