Is it just your Starry Blenny rubbing? I started a similar post a while back ago. My Starry Blenny rubs on the rocks and dive bombs into the sand. He never developed any signs of a parasite. I was told that blennies purposely do this to disturb the surface of the rocks and sand in an effort to search for food. He still does this to this day, but he is perfectly healthy. Like HumbleFish suggested, wait until you have a clear picture of what parasite, if any, you have before treating. My guess is that you're okay.