Call your doctor and ask her to call in a prescription for Valtrex, Famvir, or Acylovir, Dr. Wechsler says. If you can't reach her, and you probably won't on a weekend, you can pick up Abreva, an over-the-counter medication. If you can't make it to the pharmacy, you can try some old-fashioned remedies: Visine will help take the red out and Preparation H will reduce swelling. So will a cold compress and Tylenol or ibuprofen.
Linsey Snyder Wachalter, owner and makeup artist with Facetime Beauty, suggests lightly exfoliating the area so there is no rough skin on the top layer. Then pop a little concealer on it and if the cold sore is directly on the lip, go for a dark berry lip color or deep red—like these from Lancôme—to cover it up as much as possible.