With prep-less veneers, since the tooth is not being prepped, the result can look more bulky. Therefore, yes, this could cause the upper lip protrusion that you are mentioning. The only way to know for sure is to be seen by a cosmetic dentist (always get a few opinions) so they can examine your case and also look at your bite on the upper arch. This is one of the reasons we typically do not prefer to do prep-less veneers in our office due to the lower quality aesthetic result patient's will have. Porcelain veneers done by a trained cosmetic dentist are generally the best method to insure that the teeth will look natural, beautiful, and not bulky. Best of luck!