Blisters are small pockets of fluid in an upper layer of the skin caused by friction, burning or freezing.
Most blisters are filled with a clear fluid called serum or plasma (blister water).
Some blisters, however, are filled with blood; they are called blood blisters.
Blisters are small pockets of fluid in an upper layer of the skin caused by friction, burning or freezing. Most blisters are filled with a clear fluid called serum or plasma (blister water). Some blisters, however, are filled with blood; they are called blood blisters.
Blister