Can veneers be trimmed? (Photo)

I got my top teeth done and my left side is now longer than my right side. I regret not going with longer front teeth. My teeth look too square and straight across. Can veneers be trimmed? To even out the sides and possible make the teeth next to my front two smaller so my front teeth can look longer? Is it possible or do I need to replace them? I feel the straight across look makes me look masculine. Any suggestions please.