Weever fishes usually sting the feet of people strolling along the water’s edge. Their stings initially cause an intense pain, which may radiate toward the leg later. The skin becomes red. In severe cases it can cause a general malaise and cardiovascular diseases caused by the toxin injected by the weever fish.
What to do.
One of the most efficient ways to reduce the pain is to place the foot or the leg in hot salted water (about 45/50°C) for one hour (you can even use sea water). This will stop the circulation of the toxins.
What not to do.
Do not apply cold water or ice, do not rub the sting with alcohol or scratch the affected part: if you do that, you will only help the toxin spread.