After hearing about the effectiveness of chlorine dioxide spray from others, I decided to give it a try on my cold sore. I had already woken up to the tingle and realized that it was too late, as a 4-headed sore had started to form. I was in a panic but I sprayed chlorine dioxide on the sore throughout the day. Surprisingly, the sore did not fully manifest as it usually would have, and it began to subside within a couple of days. The sore was gone very quickly and I don’t think anyone even noticed it. I highly recommend giving chlorine dioxide spray a try.