On my, cold sores are so damn delibating, aren't they? I mean so bad for going to work, normal socialising but an absolute sh*t for a first date! I have had them really bad in the past, made me feel like a leper I can tell you, but as I have aged, they are never as bad now.
My advice? Zovirax is great ( but vastly overpriced for a 2g tube! ) but I have found that the secret is to alternate the Zovirax with periods of keeping the sore dry. I have also tried alternating applications of hot and cold applications i.e. bathe the sore with hot water on a flannel ( as hot as you can stand ) and then apply ice cubes. Don't forget to wash the flannel thoroughly after! That treatment tends to calm the sore. I would then finish that with a wipe of Zovirax, let that get absorbed and then dry the lips, then finishing off with something to keep the lip dry such as a cosmetic to cover spots. I think it is this drying process that shrinks the sore into oblivion. Everything you do should be scrupously clean though and never share anything here! The drying treatment seems particularly beneficial before sleep. And if the sore cracks and bleeds, encourage the beelding at first and then stem the bleeding with lots of tissue, possibly a styptic pencil if necessary and then maintain dryness as above. Thursday is not far away but you may be able to reduce the sore to almost insignificant. But also, be honest with the guy, he's not going to want to drop you for a healing cold sore ... if he is any man, he will take that on board and if he likes you, he will look forward even more to another date when he can get at those lips .... kissing is definately out this week! But I would add that if this is a really aggressive cold sore, and they do happen, you will be mega miserable and it may simply be better to take a rain check on the date to one week forward or something ... I mean you would always reschedule a dental appointment if you had a cold sore, wouldn't you, because that is sensible for everyone. I really wish you luck on this one ... been there, got the T shirt and all that!