Toadstool stung by Acan Echinata

About a week ago my toadstool fell over onto my acan (echinata), I don't know how long it was in contact with it, but it appears to be slowly decaying in a manner of speaking. It has two white spots on it's mantle that were't there before the sting, but it does still put out all of it's polyps.

There are no more polyps where the white spots are, and it was stung not on the mantle but on the stalk. Is the toadstool just going to slowly die or is there a likelihood that it will overcome the sting? From my understanding acan stings are pretty brutal.