Cold Sores

Frequently Asked Questions

• How can I get rid of a cold sore in 24 hours?

  While no treatment eliminates a cold sore overnight, starting antiviral therapy at the very first tingle gives you the best chance of a shorter, milder outbreak. Prescription antivirals such as valacyclovir, taken within the first few hours of symptoms, can significantly reduce healing time. Over-the-counter creams like docosanol can also help when applied as soon as you notice the early warning signs.

• What does a cold sore look like?

  A cold sore typically begins as a red, swollen patch of skin around the lips or mouth. Within a day or two, small fluid-filled blisters cluster together at the site. The blisters eventually break, ooze clear or yellowish fluid, and then crust over before healing completely—a process that usually takes 7 to 10 days for a recurrent episode.

• How long is a cold sore contagious?

  A cold sore is most contagious from the moment you first notice tingling or itching until the scab has fully fallen off and new skin has formed. This typically spans the entire 7–10 day outbreak period. Even when no sore is visible, HSV-1 can be shed asymptomatically, so it’s important to avoid kissing and sharing personal items whenever possible.

• How do you treat a cold sore?

  Treatment options range from prescription antivirals—such as valacyclovir or acyclovir, which work best when started at the first sign of an outbreak—to over-the-counter topical creams like docosanol that can help shorten healing time. Keeping the affected area clean and moisturized with a plain lip balm can also reduce discomfort and prevent the crust from cracking. A Rexall Pharmacist can assess your symptoms and recommend the most appropriate option for you.

• What does a cold sore feel like when it starts?

  Most people experience a prodrome—a set of warning sensations—12 to 24 hours before any visible blister appears. This typically includes tingling, itching, or a burning feeling on or around the lip. Some people also notice mild swelling or redness at the site. Recognizing these early signs is important because antiviral treatment is most effective when started during this stage.

• When is it safe to kiss someone again after a cold sore?

  It is safest to wait until the cold sore has healed completely—meaning the scab has fallen off and the skin underneath looks normal—before resuming kissing or other close oral contact. Even after the sore is gone, HSV-1 can still be transmitted during asymptomatic viral shedding, so discussing your history with a healthcare provider is a good idea if you have frequent outbreaks.

• Can you pop a cold sore?

  No—you should not pop a cold sore. Breaking the blister releases highly contagious fluid that can spread HSV-1 to other areas of your face or to other people. It also removes the natural protective barrier of the blister, increasing the risk of a bacterial infection and potentially leaving a scar. Let the sore progress and heal on its own, and keep your hands away from your face as much as possible.

• What’s the best thing to put on a cold sore?

  Prescription antiviral creams or oral medications (such as acyclovir or valacyclovir) are the most clinically proven options and are most effective when applied or taken at the very first sign of an outbreak. Over-the-counter docosanol cream (sold as Abreva) is the only non-prescription topical approved to shorten healing time. A plain, fragrance-free lip balm can help keep the area moisturized and prevent painful cracking of the crust.

• What causes cold sores?

  Cold sores are caused by the herpes simplex virus type 1 (HSV-1), which is usually contracted in childhood through contact with an infected person’s saliva. After the initial infection the virus lies dormant in nerve cells and can reactivate later in life, triggered by factors such as sun exposure, stress, illness, fatigue, or a weakened immune system.

• Can a Rexall Pharmacist prescribe cold sore medication?

  Yes. In most provinces across Canada, a Rexall Pharmacist is authorized to assess cold sores as a minor ailment and write prescription treatment when appropriate. They can also recommend over-the-counter treatments, advise on prevention strategies, and refer you to a physician if your symptoms are severe or unusual. Book Consultation at your nearest Rexall today.