You can try! Get some distilled water. Need a container like a tall plastic pasta salad container that you buy the pasta salad in from the local grocery and a pot that will fit inside of it. Stuff the moss with the green portions on the top side into the pot and sit the pot inside the pasta jug. Fill with distilled water and let sit for a few hours. Then drain off some of the water so that the top of the moss in the pot sits about an inch above the water level. Sit outside in partial sunlight and then spray daily with the distilled water just to get the top of the moss moist.

I am doing the same thing and I was surprised to see that the moss I bought online that came in a bag is recovering and has some live pieces growing. Give it time and hope to see it covering the entire surface of the pot.