I have no idea how long it can live outside the body. But the cold sore virus is a form of the herpes virus. So, it probably can live outside the body for a bit - especially since we are always told how contageous herpes is (including the chicken pox). If your son came into contact with the virus, chances are hes got it, but remember, many people are simply carriers of teh virus, and never break out into coldsores in their lifetime.
We live with them every they. We need to look at people who never get it and not the other way around.
I had once this bloody thing on my intimate part and how embarrassing was to go to the doctor with it. I can never forget. That was 5 years ago, since then I have done a lot of research about health and came across that a week immune system
is behind the problem.Now I'm taking a special multivitamin which you can get in health food or discount vitamins stores. If you worried about cold sore or other viruses/bacteria You may want to try this approach.