I haven't found a cure, but in all my 18 years of suffering with outbreaks of cold sores around the mouth and even nose area, several times a year, I have found something that gets rid of them relatively quickly
....nail polish remover! I thought this would burn/dry it out and so I tried it one time and now each time I feel a cold sore starting to erupt I use this. They usually clear in 3-5 days as opposed to my usual 10-14! I apply it as many times as I can throughout the day with a cotton swab. Usually I get a needle, hover a lighter over it to kill any germs, place it in some polish and then pop any blisters. Once i've done that I then get a cotton swab dab it in the polish and dab it on the affected area for a few seconds.