Stung by a pelagia noctiluca at Granadella beach (Javea,Spain)

Stung by, probably a Pelagia Noctiluca. While snorkling in the afternoon, I passed by an Pelagia. Around 19:30 I decided to take a short last swim, and got stung by a jellyfish in the hand. For more then 24 hours an incredible pain, swollen hand and the feeling of electroshock in my whole arm. Now, after 5 days, the swollen parts are gone, but it still feels like a burn wound and it itches a lot.