Have a lower biteguard and i am noticing enamel wear on my lower central incisors where i am clenching on the guard.enamel loss with a guard possible?

Have it checked: Generally you would expect the guard to wear because it is softer than tooth. Have the person who prescribed it and inserted it check it

It may: One of the down side of wearing the night guard is you preventing your saliva to reach your teeth, therefor it is easier for bacteria to damaging your teeth. My suggestion to you is proper and good oral hygiene and also buy mi paste and put it on your mouth guard after you brush your teeth and go to bed. Mi paste help your teeth to remineralize and prent you from further damage to your teeth.

Toothwear/night guar: Unlikely, the tooth wear probably is from mismatch of positions of your teeth. Enamel is harder than acrylic.

Probably not: Night guard separated teeth it does not cause wear of teeth unless it is worn out and teeth are touching, then need to be replaced.