Blister-like spot on gums, after temp dental crowns. Something to expect or should I be calling the dentist? (Photo)

While it MAY be more that what I can tell from the images, I think it is simply normal healing from the trauma of the work.  It is normal and should heal uneventfully.  Warm salt water rinses can help.

I agree with the other dentists that have answered.  I think it is simply normal healing from the trauma of the work and it should heal uneventfully.  Warm salt water rinses can help alleviate some of the discomfort.  If it continues I would call the dentist. 

What it looks like you have are aphthous ulcers on your gums. That can happen after trauma in the mouth. They go away in a week or so but shouldn't be a major concern for you, other than the discomfort. Should they continue for some reason, or cause you more pain than you presently feel you should definitely talk to your dentist. You certainly would not be "one of those patients".