unknown rash during snorkeling

[ksporry]

So, my gf and I went for snorkeling (i was scuba diving she was snorkeling). And we both experienced an unconformable stinging sensation on the surface. I did not experience it under water but on the surface it felt like tiny jelly fish stings. I had a few rash spots appear on some exposed areas, but she had it much worse. This seems to suggest whatever was stinging, was only on the surface.
Interestingly, other than the rash, there don't seem to be any other symptoms. Neither of us feels uncomfortable, itching or stinging sensations of any kind, other than then singing sensation when we were in the water on the surface.
I don't think it's "sea lice", as that usually occurs on unexposed areas of the body.
For information, we were diving in Sihanouk Cambodia (again, I was diving, no more than 10m. She was snorkeling)
Any ideas?

 

[KathyV]

It could be jellyfish larvae in the water; below is from a recent thread about this occurrence in the Caribbean, but I am sure that it can happen anyplace because jellyfish are in all the oceans.

http://www.scubaboard.com/forums/co...ce-ssnorkeling-20-feet-shore.html#post7319811

 

[ksporry]

I don't think this is the same. Although the visual symptoms look the same (measle like bumps), neither me nor my gf has any pain or discomfort. No itching whatsoever, just a few pimple/measle like bumps. My gf had it a lot more than me and is going to the doctor tomorrow. Another possibility we are considering is bad seafood. she has had a similar reaction once before and that appeared to be an allergic reaction to seafood (not confirmed though). Since we ate the same stuff , my symptoms (though less severe) may be caused by the same (maybe I ate less of it, or maybe I'm more resistant). Mind you, it looks like the rash only appeared on skin areas that were exposed during our water activities, and she complained a lot more about micro stings than me. So it may still be jelly larvae stings. I guess we'll find out when she goes to the doctor tomorrow.