I have to agree with what Todd said here, would have said the same thing myself.
Those spots are usually considered scar-like spots because they are usually caused by a fish hosting a coral that can sting (i.e. Zoas, Frogspaun, Xenia). Do you know where the fish sleeps at night?
If that is not the case this could be somthing else but at this point doesn't sound like it is affecting eating or the way the fish is living up to now.