This condition you usually experience, which is blisters around the lips is also called cold sores. They often appear as sores or lesions not only around the lips but sometimes inside the nostril, on the cheek or chin and in less frequent manner, on the gums in the mouth or the roof of the mouth. They are often accompanied by severe pains, burning sensation or itching on the spot where they develop. They are also called fever blisters.
The main cause of cold sores is a virus strain called herpes simplex virus1(HSV1). They are highly contagious as they can be passed on from one person to another easily through direct contact with an infected person. The good thing about them is that, they have time duration for them to burst and disappear, which is 7 to 10 days. Cold sores can be activated after disappearance by minor triggers like injuries and fatigue.
Unfortunately, cold sores can not be cured but through self healing process, they can be treated after their time of duration elapse.