Blister/ˈblɪstər/ Definition 1 of 4Pro Tip 1/3Skin Irritation Use 'blister' when skin swells due to friction, like from tight shoes. I have a blister on my heel from hiking. Pro Tip 2/3Protective Healing Blister indicates a natural body process to protect injured skin. Don't pop the blister; it's protecting the burn. Pro Tip 3/3Pain Association Blister often suggests pain or discomfort, especially when walking. These new boots gave me painful blisters.