Any idea what's on this damsel?

[Royals Fan]

Any idea what is on my damsel? The spots started showing up a few months ago and have increased. He seems to be fine and is eating well. However, as you can see his color is very faded and that started with the spots.

Any identification or treatment ideas would be a big help. One additional unusual behavior. I just got a peppermint shrimp and since the shrimp arrived, this damsel seems to swim up next to him and just stay by him. He isn't being aggressive to the shrimp, but he just keeps coming back and staying right next to the shrimp. I can't see that the shrimp is actually doing anything to the damsel.

Thanks for the help in advance!