Cold Sore Symptoms

• Some patients have a "prodrome," which is when certain symptoms occur before the actual sores appear. The prodrome to herpes infections typically involves a burning or tingling sensation that precedes the appearance of blisters by a few hours or a day or two. As the cold sore forms, the area may become reddened and develop small fluid-filled blisters. Several of these small blisters may even come together and form one large blister. Cold sores are mildly painful.
  
  
• When cold sores recur, the blisters dry up rapidly and leave scabs that last anywhere from a day to several days, depending on the severity of the infection.