Whichever cold sore treatments you decide to try, it is best to do so as soon as you see the signs of a cold sore. Even then, you should know that there are no proven cures for cold sores. At the most, what you can expect is that the treatment you use will reduce the pain and will also lessen the duration of the cold sore. There are several factors that can cause cold sores such as stress, illness or fever as well as menstruation and certain types of foods. If you are prone to getting cold sores, it is best that you stay away from these triggers.