These sports hydrocolloid blister plasters have an adhesive wound dressing that is laminated to become semi-permeable, bacteria proof and waterproof. The plaster itself forms a gel (that can show through as turning white in colour after a few days) as it absorbs any liquid in the wound, this provides a cushioned, moist environment which allows the wound to not have to make a scab but start healing from the inside out. This speeds up recovery time and reduced scarring later on as well.
Clean the area first with soap and water and dry thoroughly as oils and moisture will reduce adhesion. Warming the plaster in the hands first will also aid the stickness of the plaster. Leave the plaster in place until it loosens naturally, hopefully for 4-5 days if not over a week.
Do not use on infected wounds or if you have diabetes or circulation problems.