Looking for info on repairing my bathtub acne.

My house was built in 2002. It has a single piece bathtub with wall
surrounding it. I think the tub and surrounding walls are fiberglass
but I am not sure.

We have a young daughter, so to entertain her while bathing we bought
some 8x11 sheets of plastic that have pictures of animals and shapes.
These sheets are the kind that stick to the wall when they are moist.
The sheets have been on the bathtub walls for a few months. We noticed
that when we removed them yesterday that there are a bunch of 1/4 inch
bubbles that have formed in the fiberglass wall. In total there are
about 50 bubbles that have formed behind the plastic sheet that we had
hanging.

I am trying to figure out the best way to repair. I see that there are
repair kits to fix cracks and holes but I don't see mention of
bubbles. Can I sand these out and then use a kit to repair the tub?