It doesn't quite look like BJD, so I don't think you need to do anything rash right now, but if it truely were BJD, I wouldn't wait until your next water change. If it starts looking worse/spreading or you are able to suction up any of the "jelly", I would pull the coral immediately- on torches, about half of the heads I've tested seem to die in under 24 hours from first symptoms. Here's a write up for a step by step procedure if it turns that way:
Current Treatment Strategies for Brown Jelly Disease I’ve been asked to summarize the current findings concerning Brown Jelly Disease for those that need a quick reference if they encounter it in their own tank. For a link to current tests investigating possible treatments, see here. First, if...