It appears that this area may have been under water at one point??? Fixing, means popping and grinding out each of these blisters. Most likely they are only gel coat, not more invasive blisters as seen below the waterline. I have seen several C Dorys where that has occured. Some of these I suspected had a problem with gelcoat adherence or contamination when sprayed into the mold. The "cure" is to remove the gelcoat down to the next layer. Sand, fil--if more than a couple of mm deep, then use some glass mat in the repair. Fair, then recoat with gel coat. C Dory White Gel coat is not easy to get a perfect match "Hatteras White" in paint is close---and it will fade with time.
I would take a more agressive approach, do the filing with epoxy, then lay down epoxy primer on the topside hull part of the boat, and paint it with one of the two part L P paints. Such As Awl Grip or the specific paint for that application. Either spray, only if you have expertise. Easier for an amatuer would be to tip and roll, a special solvent for each different type of application may be necessary. Most extensive blistering I have dealt with was below the waterline, and went down several layers as you ground out the glass to replace it.
