Cold sores, or fever blisters, are caused by the herpes simplex virus (HSV-1). Once contracted, the virus remains dormant in nerve cells, reactivating due to triggers like stress, illness, hormonal changes, or sun exposure. The blisters typically appear around the lips, nose, or chin.

Initial symptoms include tingling, itching, or burning before the blisters form, burst, and scab over, healing in two to four weeks. Treatment options, such as antiviral medications (acyclovir, valacyclovir), and over-the-counter remedies, can speed healing and reduce discomfort. Natural options like aloe vera may also help.

Preventing outbreaks involves avoiding triggers, managing stress, using sunscreen, and strengthening the immune system. Cold sores are highly contagious, so good hygiene and avoiding close contact are key to preventing spread. There is no cure, but ongoing research may lead to better treatments.