What Causes Water Blisters On Arms And Elbows?

I keep waking up with big water blisters on my arms-in my outside elbow area. I first notice my skin burning & then by the end of the day a big water blister forms. When it breaks it burns & hurts so badly!!! I went to my doc & he gave me an ex for antibiotics but didn't help. It has happens twice since I've seen him. I'm getting worried. Could it be a bug? I've completely stripped my bed (Tempurpedic) and also spayed it all down with Lysol. I also washed our down pillows. The water blisters start out with a clear yellow fluid about the doze OT a quarter. Any ideas?