I have never been personally stung by a jellyfish. However, if I was even stung by a jellyfish, the first thing I would do is see a doctor. The treatment for the jellyfish sting includes first aid care and medical treatment. It depends on the type of jellyfish, the severity of the sting and your reaction to it. You have first to rinse the area with vinegar, pluck the tentacles, soak the skin in hot water, keep the affected skin immersed in hot water for 20 to 45 minutes. Do not rinse with seawater or apply alcohol.
If a jellyfish sting happens near or on the eye, prompt medical care is needed for pain control and an eye flushing. Someone with this type of sting should see an ophthalmologist.