arent a terribly big problem and many of the previous posters have good suggestions on how to fix them. But most blisters
are cosmetic, the real problem is hydrolysis. Drying out the boat and patching the blisters will just make the blisters go away. Because you cant dry out the boat completely there is still water
inside the laminate. Over time the water
will weaken the laminate and form new blisters again letting more water into the laminate and then the whole cycle just repeats.
The only way to really get the water out of the laminate is to recognize the unfortunate fact that the already osmotic laminate cant be save. The only solution that has a real shot of preventing blisters for the rest of the life of the boat is to remove the affected laminate, have new laminate put on using top grade gel and barrier coatings, and constant vigilance