its quite big one in the corner of my mouth.i cant open my mouth :I

Put ice on it to stop swelling then add loads of moisturizer

Put ice on the affect area, it will stop it from growing anymore

Haha... I read that as "coleslaw" first time round.

You mean "coldsore". You need to go buy some Zovirax.

make sure you don't lick your lip where it is because it will make it worse

Dab a bit of aftershave on it, or you could use Zovirax whcih is pretty good

is it a coldsore or just chapped?
coldsore-abreva, mustard
yes mustard, just put it on the coldsore and leave it there till mornig.
chapped-leave it alone

cover it in toothpaste, it may sting abit but it always worked for me,

If you have never experienced a cold sore it begins with a slight tingle or itch on your lip. At this point there is no pain, but you know it's coming. When you feel this sensation there is now a prescription drug that can put a stop to it. The drug is manufactured by Glaxo. What's the name of the miracle drug? It is called Valtrex. But no once it comes out their is no possible way to get rid of it, it's a virus a type of Herpes, once it goes you still carry the virus in your system hence some people get them some people don't. You could also try herbal remedy's such as white vinegar, toothpaste and mustard.