After treating the sting right away by rinsing away the venom and removing the tentacle, you can treat the rash or any blisters that occur with home treatment.

Home treatment that you can try includes:

• Applying heat to help reduce pain.
• Taking an over-the-counter pain medicine, such as acetaminophen (Tylenol), ibuprofen (Advil, Motrin), or naproxen (Aleve). Be safe with medicines. Read and follow all instructions on the label.
• Using an over-the-counter hydrocortisone cream for itching.

If a deep sore develops, you may need medical treatment to help the sore heal and prevent infection.

When an itchy rash occurs several days to weeks after a sting, the rash may mean a delayed skin reaction has occurred. A delayed reaction can occur weeks to months following a sting. You may also have a fever, weakness, or joint stiffness or swelling. Medical treatment may be needed to prevent problems from a delayed reaction.

Seabather's eruption is a rash that develops after the sting of certain jellyfish or sea anemone. The rash can be itchy and annoying. But it usually goes away with home treatment in 1 to 2 weeks.