Tara's post reminded me of my own thoroughly unpleasant experiences with the dreaded ... cold sore. There've been a couple of times in the past when I've had to deal with continous cold sore attacks (it really is possible to get one attack after another) which lasted months or more.
This is the reason why the word 'crusty', for me, is not synonymous with the word 'baguette'.
The first time I had the continuous nasties, I thought it was because I was dying to go overseas already. Funnily enough, I was completely free of them about two months after I started my first job in Edinburgh, until I returned to New Zealand two years later.
Personally, I believe world travel cures a range of maladies from acne to loneliness and boredom.
The next time it happened, I couldn't figure out what stress factors could have caused it. I was happily in love, had just left my much-loathed (by then) IT job and was a full-time 'artist'. I'll probably never find out. Anyway, the thing that saved me from everlasting nastiness was a year-long course of Acyclovir.
Now I can do all manner of front-line customer service tasks without scaring small children (that's semi-sarcasm).