Fever blisters, or cold sores, appear as small, fluid-filled blisters near the lips, nose or cheeks, according to Mayo Clinic. After the blisters burst, they look like shallow, open sores that drain fluid and eventually crust over.
Certain strains of the herpes simplex virus, or HSV, cause cold sores, explains Mayo Clinic. These types of sores generally heal without treatment in two to four weeks. However, medical practitioners sometimes prescribe antiviral medications to speed up the healing process.
Applying pain-relieving creams or cold compresses can help minimize the discomfort of a cold sore, recommends Mayo Clinic. Patients should protect their lips with lip balm and sunblock when a cold sore is present.