Is this an open margin?

[Sunflowersnsapphires]

Had my veneer replaced on tooth #8 in September. I noticed shortly after that the veneer does not touch my gumline and I can see the edge of my veneer. I recently saw a different dentist locally for a check up and x-rays. I asked him about that tooth. He said there wasn't an open margin. However, I can fit my fingernail behind the tooth and I’m having some sensitivity to hot and cold. He adjusted the bite. But I’m still not totally convinced that this tooth is completely sealed. What are your thoughts.