Pinhole and blister are all defection of glaze. Pinhole could go down to the body/paste of the porcelain ware. Blister is more like the crater direct on the surface and induced by the blasting of one bubble or bundle of bubbles on the surface of the glaze.  Generally, both pinhole and blister are smaller than a head of a pin. Since the blister is generated from the bubble explosion, it is not easy to see by eyes. Instead, most dark points we observed on the surface of porcelain ware are pinholes.

Pinholes could be seen on most of antique porcelain wares and also the defect problem for modern ceramic industry. So, it is questionable if we could use the pinholes as a feature to tell the authenticity of a porcelain ware. However, we could put more attention on the blister. In the naked eyes blister is not so obvious, most just like some light points distributed on the surface, the feeling like watching the skin of orange.