From the Back of my Veneer Tooth when Rubbing my Tonuge to Feel the Veneer with my Tooth It Feels Like a Small Dip/Crease?

The "dip/crease" at the porcelain laminate veneer margin on the lingual (inside) surface of the tooth is often a sign of an open or poorly adapted veneer margin. This can happen if the veneer was manufactured with a "short margin" or there was too much composite resin luting cement used in the seating process which can create a barrier to the veneer seating fully over the prepped tooth. While the composite resin cement tends to fill voids in and around the veneers, if excess cement is trimmed/cleaned away prior to being fully cured (set), the resulting cure shrinkage of the cement (which normally occurs) can cause the dip or crease that you feel with your tongue. This is an area that should be monitored for "leakage" or recurrent decay under the veneer and I would recommend filling that space with a small amount of flowable composite resin if the gap is significant. I do not recommend trying to file it smooth as that would result in the reduction of additional tooth structure and veneer material. 

Occasionally the junction where the veneer meets the prepared edge of the tooth may not fit precisely or the veneer may be shallower than the prepared tooth. The bonded veneer cement will usually fill any minor discrepancies and will feel smooth. Perhaps some cement was removed during the polishing phase revealing the minor discrepancy. This area could be re-bonded and "filled" in with a flow-able cement. Sometimes trying to smooth the area will enlarge the "gap" and could make it worse in the long run. I would recommend  flowing in the bonded resin cement and then smoothing everything together.