Concrete behind liner starting to poke through

I just found what feels like a concrete splash behind the liner and it is wearing away at the liner; some of the print is already coming off. It is right at the water line.

What would be the best way to fix this? I think the wearing away is from my Dolphin cleaner brushing on that part.
Can I pull the liner out of the coping and remove the concrete? How difficult is it to pop out a small section of liner and put it back?

My husband thought he could just hit the concrete with a hammer and cloth covered block to pulverize the concrete. Is that a viable option? I am afraid of him doing more damage to the liner.