I had a very bad time with coldsores when I was 23. It sounds daft, but they were occurring so regularly, and taking so long to clear up, that I started to avoid people. Eventually a girl in my work put me in her car, and drove me to her g.p. Coldsores are caused by Herpes Simplex virus, and the doctor prescribed Heplex D liquid, for any future coldsore episodes. (At the time I needed other treatments, as I was very run-down).
As long as I got the Herplex D stuff on AT THE VERY FIRST sensation of itch or tingle, it worked. I would not go out without my little bottle! It was my most prized possession. It was on many a foreign beach with me - that's another thing to note, exposure to strong sunlight can also cause a coldsore, even if you haven't got a cold. If you've had one coldsore, the virus remains in your system, so you need to be vigilant!
Zovirax came out a long time after that - an ointment that could be bought over the counter. Again, it's a matter of getting it on
as soon as you feel a tingle.
I haven't had coldsores for years. My diet was really bad back then, and that coupled with lack of sleep and stress had my immune system weakened. It's the same with colds, I think. It makes sense to look after yourself a bit. But if you get them in time, there's no need to suffer.
