How long does a cold sore last?

[Rafaella]

Having reached half a century without ever suffering a cold sore I am now making up for it with a huge sore at one corner of my mouth with another now starting up on the other corner. I've had the first for about 10 days and it's still weeping and cracked and very painful, with horrible crusts. The smaller one started a few days ago and is getting bigger. When I open my mouth to eat it opens them both up again. Luckily I work from home as I do not feel like leaving the house. I'm using Zovirax but it doesn't make any difference, I know I started too late with it. Any miracle cures?

I've never found a miracle cure. Had cold sores since childhood and am very lucky if they disappear before 10 days. Zovirax will keep an incipient one under control i.e. stop it breaking out completely but it has to be put on at the very first tingle, literally within minutes.. Otherwise too late, as you say.

Poor you. I sympathise. Bastard things.