Fullsuits, vinegar, meat tenderizer and antihistamines are a must if you're in any way sensitive. I always pack them in my dive bag.
Oh, to be able to dive in boardies or a shorty or a bikini! I'm the lunatic in the fullsuit in 31C. Some people are just strangely more sensitive to those little stingers than others. The last time I went for a dive in a shorty, I developed huge angry horizontal welts from the tops of the thighs to the top of my boots and on my hands and in even between my fingers, essentially every place that wasn't covered by the suit. You could even make out the tentacle formation. Everyone on the dive felt a little fleeting sting but no one else had a reaction close to mine. I grew up in South Florida and was savaged by "sea lice" every time I swam in the sea. I used to think I was just allergic to the ocean. I haven't made it to Oz yet, but I reckon I'll need about the same coverage as Spiderman!