Most people who become infected with the virus that causes cold sores never develop symptoms. However, they still may be contagious to others, even without blisters.
For people who do develop signs and symptoms, a cold sore usually passes through several stages, which include:
- Tingling and itching. Many people feel an itching, burning or tingling sensation around their lips for a day or two before cold sore blisters erupt.
- Blisters. Small fluid-filled blisters typically break out along the border where the outside edge of the lips meets the skin of the face, although the blisters can also occur around the nose or on the cheeks.
- Oozing and crusting. The small blisters may merge and then burst, leaving shallow open sores that will ooze fluid and then crust over.
Symptoms can vary, depending on whether this is your first outbreak or a recurrence. During first-time outbreaks, some people also experience:
- Sore throat
- Muscle aches
- Swollen lymph nodes
Children under 5 years old may have cold sores inside their mouths and the lesions are commonly mistaken for canker sores. Young children are also more likely to spread the virus to other locations on their bodies, such as their fingers or around their eyes.
When to see a doctor
Cold sores generally clear up without treatment. However, see your doctor if:
- You have a weakened immune system
- The cold sores don't heal within two weeks
- Symptoms are severe
- You have frequent recurrences of cold sores
- You experience irritation in your eyes