First aid for stinging things, remove the stinging things,(tweezers, forcepts) then apply hot water. (as hot as you can stand as long as you can stand it without burning the skin, )
Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.
Benefits of registering include

Bristle Out Lol!!
I wonder if you would treat it like a jelly sting? That's what the pee jug is for!!
First aid for stinging things, remove the stinging things,(tweezers, forcepts) then apply hot water. (as hot as you can stand as long as you can stand it without burning the skin, )
I'll stick with vinegar. I have no experience with fireworms (I like hydroids myself), but I've been told by a few people that have "snuggled-up" to the cute little worm that applying vinegar on the affected area as soon as possible does about the same thing for a fireworm encounter as it does for hydroids. Supposedly, it helps prevent any of the bristles that haven't fired their venom, from firing. After that, hydrocortisone helps with the itching.That's what the pee jug is for!!