I was just outside cutting the grass on my tractor when something caused an immediate sting to my ring finger, right hand. Then, very shortly after that, something stung my left shin, then my left knee. There are tiny puncture marks, surrounded by a little redness. All three are continuing to sting, like I'm getting stuck with a needle. I saw no insects at all, AND MY HANDS AND LEGS WERE COVERED at the time! What could this be????? Thank you