The space in which you describe and the photo shows is commonly called "the black triangle." As stated by another dentist, this is sometime difficult to predict whether or not the gums will fill in the space. Giving it some time will allow us to see if it resolves or if it is something that will remain.
Factors that may determine whether remaking the veneer are:
1) Size of the original tooth and how much space did the dentist have to close... The smaller the tooth and the more space, the more difficult it is to improve the gum line
2) Anatomy (or shape) of the veneer... If you're happy with the esthetics or look of the current tooth (excluding the gum issue), then remaking the veneer has some considerations that you will need to decide whether it is worth replacing it. For the dentist or lab to close the gum space, the new veneer would have to be slightly more square-shaped to close the space.