Lionfish (as well as scorpionfish and stonefish) possess dorsal, anal and pelvic spines that transport venom from venom glands into puncture wounds. Common reactions include redness or blanching, swelling and blistering (lionfish). The injuries can be extraordinarily painful and occasionally life-threatening (in the case of a stonefish).
Soaking the wound in non-scalding hot water to tolerance (110 to 113 F / 43.3 to 45 C)
If the injured person appears intoxicated or is weak, vomiting, short of breath or unconscious, seek immediate advanced medical care.
Wound care is standard, so, for the blistering wound, appropriate therapy would be a topical antiseptic (such as silver sulfadiazene [Silvadene] cream or bacitracin ointment) and daily dressing changes. A scorpionfish sting frequently requires weeks to months to heal, and therefore requires the attention of a physician. There is an antivenin available to physicians to help manage the sting of the dreaded stonefish.
For more information on marine life injuries, see the complete article by Paul S. Auerbach, M.D., M.S. on Marine Life Trauma from the Jan/Feb 1998 issue of Alert Diver.