Welcome to the GERD Forum at Healing Well! No, you are not getting esophageal damage when you are on PPI's. I can say this with authority, as my surgeon who recently did an endoscopy on me, said that they rarely see inflammation any more, as most people are on PPI's.
During the time I was still having occasional breakthrough heartburn symptoms, but was on PPI's, I never had inflammation of the esophagus.
So...you are protected if you remain on PPI's.
If anybody reads this and have a different opinion, chime in. I'm going on my recent conversation with my surgeon.