@ZipLine-- Cold sores are triggered by cold and the virus that causes them also gets activated when the immune system weakens. That's why they're more likely when we're ill or in winter when our lips are chapped. You do need to keep your lips moisturized to prevent cold sores. You can also take a lysine supplement. Lysine is an amino acid and it has been proven to reduce cold sore breakouts. If you take it at the first signs of a cold sore (tingling), you can prevent them. Even if you can't they will heal faster. I haven't gotten a cold sore in a long time thanks to this supplement. You can get it from the pharmacy.