Kaye--
Lionfish venom is very different than bee or wasp venom. The pain is similar, only because your bodys reaction to either is similar.
Lionfish venom is a composed of mainly acetylcholine and a few dozen proteins, its role is too overwhelm the closest nerves, and immediately cause an intense reaction. Remember lionfish venom is purely a definsive weapon, it is not designed to stun, kill, digest, or mame like a snake, but lionfish and other scorpionfish use it to prevent other fish from grabbing, eating, harassing them. Hence the composition, cause immediate serve pain and too move away.
Scorpionfish venom varies w/ species but dosage is really what dictates how painful and potent it is. The spines that deliver the venom act like hyopodermic needles and adjust how much venom gets pumped into the wound. So a stonefish w/ short wide stubby spines deliver a very large dose, while a P volitans lionfish w/ thin little dorsal spines deliver smaller doses. Hence in humans, stonefish are considered lethals, while Volitans lions hurt like bee stings.
In fish, depending on its size, lionfish stings can be painful, resulting in cowering for a few days or lethal, its all dose dependent.
Finally the good news is that scorpionfish venoms are composed of primarily heat labile material and hence immersing the area in non scalding hot water for at least 30mins will reduce the pain, discomfort, and long term effects. However, it still hurts like crazy.
frank