I have encountered the same problem om my Hunter 34 only I have about 100 to 150 small blisters, most of them already split open. It was recomended to me that I grind out each blister, let every thing dry out then fill each cavity with thickened epoxy
resin after filling each repair
coat each area with unthickened epoxy
resin to seal the repair
. After the repairs
are made I am going to apply a Barrier Coat over the entire bottom. Hopefully after all of this work I will not have any problems for many years. The recommondations were made by the folks at Tidewater Marina, Havre De Grace, MD. Hope this is helpful.