Burn blister, day 3. Image 2 of 5. Patient's palm with a blister caused by a second degree burn from a sparkler (type of firework). Second degree burns affect the upper (epidermis) and lower (dermis) layers of the skin. There is no underlying tissue damage, although scarring may still occur. Burns reduce the skin's defence against airborne bacteria, making infections on a burn site a major concern. Burns are generally treated with an antibacterial dressing or left exposed to heal naturally (seen here).