As Wallua boy stated, I was stung about a week ago, when I stepped on one in about 4 ft of water off the coast of Panama. People have been getting stung here left and right lately, I believe a cold current is driving them near shore for warmth. I should have been doing the sting ray shuffle, would have saved my self some grief.
Lots of blood (which I consider a good thing), my shoe was full by the time, I walked the few blocks back to the house.
The pain is immediate, mine was about a 1" razor cut, and maybe an inch deep, I was lucky the stinger didn't break off on the bone.
I soaked my foot in the hottest water I could stand which seemed to neutralize the toxin, and aided in having the the sheath of the stinger ooze out. Soaked it for at least an hour, adding boiling water every couple minutes, and left the wound open that night.
The pic is from the next day.
There is still a dull pain a week later, and a little numbness, but I figure its temporary