If you are planning on keeping this boat for a long time .... Only if the blister are large and penetrating into the structural 'roving' layers should you consider peeling, blasting, etc. Most 'blisters' will be found only penetrating into the 'cosmetic' fiberglass layers.
You'll find most 'blister stuff' is mostly 'hype' ... unless youre planning to soon sell the boat! The 'hype' is that most 'blisters' are only into the 'cosmetic' layers (gelcoat or fiberglass matting layers) and rarely into the more important structural 'roving' layers.
Be VERY careful with DIY repairs, as most eventually fail or the DIY job is sooooo bad that most 'knowledgeable' future buyers will simply walk away from a boat with previous DIY blister repair unless that DIY job was 'perfect'. A buyer with a critical eye will usually pass up a boat with a half arsed DIY 'blister job' but will still consider one with blisters that werent 'screwed around with'.
Can you do a DIY blister job thats only into the cosmetic gelcoat or its cosmetic matting??? ... sure you can; but, you have to be damn sure youre not making the entire situation worse. Many 'boat yards' can do a $#itty overpriced job that will cost you a 'major bundle' .... and still fail again in the future.
Here's a good starting point on reference articles to help make your 'decisions': Hull Blisters on Boats and Yachts - by David Pascoe, Marine Surveyor
If you hire ANYONE to do a complete 'blister job' you should get a written guarantee that subsequent blisters will not reoccur within a defined time limit ... and that will usually drive the price beyond the gross national product of many small countries.
Do diligent research beforehand for any 'blister job' .... or simply do minor surface blister repairs and sail the boat until it sinks.
Good luck. ;-)