You could rub it off, but it won't harm anyone to leave it be, it would only come back anyway. Just let it take it's course and die out. Once you have a cuc they will take care of any left overs for you.
You might want to cut the lights a bit too(2hrs or so) until your resolve the issue.
Fix your fins or get your fins fix
+1 on that there in it for the money if you go in there looking for the most exspensive fish they will sell it to you. My local reef store actually will do a slight background check ask you a bunch of questions and make sure you know what your buying which I like.