Encountered thousands of sting rays over the years, but have been fortunate in not ever being stung - or spiked - by one.. I used to hover right over them on dives while they were buried in the sand, but stopped doing that after the Steve Irwin incident..
I think your best chance of getting nailed by one is probably while walking in the water and stepping on one buried.. I'm sure it hurt like hell, but I have no personal experience with it.. I have been attacked by a Green Moray Eel, but LUCKILY he hit my camera or I'd either be missing fingers or have had around a 50 stitch wound, at least..
Anyways, hope ya feel better.. when I walk through shallow water, I kind of shuffle my feet so as to try not to step on a ray - something tells me you'll probably adapt a similar strategy..
Friendship is like peeing your pants.. Everybody can see it, but only you can feel the warmth..