Replacement veneers, teeth filed down by 2mm. Are they permanently damaged?

The amount of preparation of the teeth for a porcelain laminate veneer restoration can vary significantly depending on a number of factors. If the teeth had prior fillings, or decay, or were misshapen, or had prior veneers done, it is not unusual for there to be a need for additional preparation (filing) of the teeth even by 2 mm in some cases. Generally, a porcelain veneer preparation is more conservative, with some cases filing only a half millimeter (0.5mm), and even none at all (prep-less veneers). It al depends on the condition of the teeth prior to treatment. I would not be alarmed if there is more reduction in your case as there were previous veneers removed. Nevertheless, I am surprised that your dentist stopped to take x-rays in the middle of a procedure to check the preparation and vitality, as preoperative x-rays should have been carefully reviewed prior to beginning.  

please upload pics of teeth preparation. otherwise its very difficult to say anything. in your case its re veneering , so little more preparation is must.