Jelly fish sting koh phangan Thailand

Today swimming off the Malibu beach in koh phangan I was stung in the wrist by a small jelly fish. It was smaller than my fist and a dark enough color for me to be able to see it clearly through the water. It burned my wrist and left a line of red dots where it's tentacles made contact. The pain was not unbearable and subsided after about an hour so I don't believe it was the infamous box jelly.