Sound like Head and Lateral Line Erosion (HLLE) starting out. Sooner or
later the holes become bigger and infested with flaggellates, until the
fish eventually dies, if left untreated.
To treat, use metronidazole (flagyl) to kill off the infestation and
infection. Feed the fish a vitamin rich food and perform two water
changes of 30% a week, until the problem abates.