My maroone clown has a white mouth

[Trigeek]

I noticed Thurs night that my maroone clown has a "white" mouth. It looks like the white is inside the mouth along the lower lip. He is eating and acting normally and his tankmates (a sixline and bicolor blenny) seem fine. All parameters remain stable. I did requascape the whole tank over the last few days. Could he have been injured in the process?

Here are some pics. I apologize about the lack of clarity.

 

[Trigeek]

No change. No better, no worse, no change in behavior, eating well, breathing well, swimming well, still comes and "greets" me at the front of the tank.