Paulness, We both probably have cold sores caused by herpes. I use Abreva at the first tingling feeling. By following the directions, I have been lucky that the cold sore never fully breaks through so it only lasts a day or so. The main thing that helped me was by using it at the very first feeling that it was coming on. Have you tried Abreva? If not, give it a try. It's not cheap but it is sold over the counter and you only need to use a little each time. The tube is only .07oz. and sells for approx. $15 - $17 but it lasts quite a while because you only use a tiny bit each application. Hope this info. helps you heal faster.
Arnold