Yag Laser for Sun Damage?

The Yag laser removes sun spots and you will have a scab or crust for several days.  I have not seen blisters but it sounds like it is too much heat.  The typical Yag can take two weeks to heal.  If you blistered and hyper pigmented this is not typical.  For all of these cosmetic procedures you should find a board certified Dermatologist who has a lot of experience in cosmetic dermatology.

What you have is post inflammatory hyperpigmentation, and honestly, it can take years to go away. You should absolutely NOT be blistered from a procedure like this. I would suggest you maybe not return where you did the procedure, since the treatment and now follow-up advice is absolutely wrong. You need to keep any blisters moist and do not pick them (which again, you should NOT have from laser like this). You also must use a good sunscreen every day because burning the hyperpigmented spots will make them continue to get darker and last longer. If the spots start peeling or turning white, then you're going to have hypopigmented areas (which are undercolored areas). I would not suggest any more treatments until you see a physician.