Is It Okay for the Metal Part of the Crown to Be Exposed at the Top of the Tooth? (photo)

During the wisdom teeth removal a crown popped off and was reattached. Afterwards, that side felt higher than before; a very uncomfortable bite. They used a drill on the crown and the tooth above it to help that. My bite is now okay but I was told that the porcelain on the crown is partially gone, exposing metal. Is it okay? Will having metal exposed change my experience eating or even damage the opposing tooth? Should ask them to replace the crown altogether? It's been there for 6ys. Thank you!