Just an update for anyone with the same problem. The white patches thankfully turned out to be stings from the coral and they went away in about four days.
I added four mushrooms, candycane coral, xenia, and gsp.What corals did you add? It's also possible it could be a burn from a tank heater if it's in your display.
It might have been the candy cane, I caught them a few times rubing against it. Yes I was warned that xenia and gsp can take over but I decided to take my chances, plus I love the look of the gsp.Looks like the only one that really stings is the Candy Cane. Mushrooms technically can sting but have very short tentacles. Any chance the clowns tried to have one of these corals host them? Also you are aware that Xenia and GSP can be invasive, right?