Sea Urchins can sting if you step on them or handle them accidentally. Once got stung, there can be intense pain, burning, local muscle aching, redness, swelling, and tattoos at the site of spine punctures. Remove the spine fragments but do not crush any remaining fragments. If there are pedicellariae attached to skin, spray shaving foam and remove them away with a razor. Try to immerse the wound into water that is hot to touch but not boiling for 30 to 90 minutes or until significant pain relief. Watch closely for any wound infection like increase in pain, pus, or swelling. Sometimes prophylactic antibiotics is required to prevent secondary bacterial infection.
If severe signs or symptoms occur, like dizziness, syncope, generalized paralysis, or difficulties in breathing, seek medical advice as soon as possible.