
My very limited experience with jellyfish in HH has me thinking that jellyfish here tend to be in loose categories of brown, red, white, and somewhat clear, some spotted and some not. Within the loose categories, there are overlapping characteristics.

The brown and red jf have the most serious stings and can burn the skin deeply, sometimes leaving scars. From what I've seen, the pain is severe; just a quick brush-by from even a smallish brown or red jf is serious.
I was swimming with a friend of mine several days ago who got stung. We found ourselves in what seemed like a school of jf and were probably lucky to get clear of them with only one sting. It was just a brush against the skin, but enough for my friend to be in significant pain for which pharmaceutical remedy was sought, including ammonia to neutralize the toxins. (Urine is sometimes recommended, too.) The pain lasted more than a few days and looked like it was a serious burn, which in fact it is.
There was a similar situation which occurred today with a friend who was caught by surprise and stung by a jf. It had appeared there weren't any about, and we had been carefree in our swimming and I suppose careless. The sea may seem free of jf but it’s not necessarily so.
This take a different turn now. My friend is Thai and treated the burn by using nature to neutralize the sting.
According to the doctor who treated my first friend, jf stings are treated differently based on their physical characteristics, in that different toxins are released. That being said, my Thai friend didn't worry about the jf’s characteristics, and didn’t waste a moment in getting out of the sea to fix a remedy. I was skeptical but since I don't speak Thai I watched, learned and know what I'll do now if I get stung.
pot bpl*i talee (pot boo talay) is a leafy vine, and my friend went directly for the leaves, picking five or six. Rolled around in the hands, there is "leaf juice" which was rubbed on the area of the sting for a full ten minutes. After a half hour the area that had quickly reddened after the sting was greatly diminished in size. It was almost hard to find and there was no complaint of pain.

I am announcing my disclaimer for responsibility here, because I don't know what I'm talking about, and half the time I just make it up as I go. This post is just a translation of my inexpert experience.
I loosely translated what the vine or leaves are called, and I think it’s something like “rash-release-seaâ€