Retainers or night guard with veneers? Could a nightguard serve as a retainer?

I have upper and lower veneers. Prior to these, I had Invisalign. My O only placed a permanent retainer on the lower teeth. He stated that my bottom teeth will hit the retainer if he puts on the upper teeth. I have bruxisim. What kind of retainer can I get without damaging my veneers? Will the molding impression for a nightguard damage my veneers? I remember it being difficult to remove when I got a crown and I’m afraid it loosens my veneers.