I first started getting cold sores when I was 15 and they were miserable. Burning blister that eventually broke and then hurt for days and the skin cracked. When I was about 40, a naturalpath MD in Sedona AZ. Told me to get a piece of blue glass and as soon as I felt the burning sensation on my lips, let the sunlight filter through the blue glass onto the coldsore. Ever since I've done that, I have not had one coldsore form into a blister. It may take a day or two of putting the filtered sunlight on the cold sore ( I do it for about 3 minutes or until the pain or burning sensation subsides, and I'll do that 3 or 4 times the first day or whenever it begins to burn or hurt again). Usually, after about two days (sometimes three if it is a bad breakout), the cold sore will have simply vanished, without ever blistering and popping. I find it is important to get the blue light therapy started as soon as I feel the coldsore coming on, although even if I miss it or there is no sunlight, this therapy works even if it advances to a blister--it shrinks the blister without it ever breaking. I found my piece of blue glass in the ocean and used that piece for 18 years now. Just this year I bought a set of blue glass dishes from walmart and tried it with the small cup saucer plate and it worked. It actually was easier because I didn't have to center my small piece of glass over the coldsore. I do cover my eyes so I don't get sunlight in my eyes while doing the blueglass therapy. I hope this will help someone. I was just telling my wife that I was surprised that this therapy wasn't in the prescription for natural healing or more widespread in the alternative healing community. It has made my life alot less painful.