Blisters are small pockets of fluid that form under the top layer of skin. They typically have very thin walls and are usually filled with clear liquid or pus. Blisters are formed when excess friction, and usually heat, damage the skin. Most people find them on the hands and feet. They are a common affliction in runners, those who wear dress shoes or heels, and people who wear shoes that do not fit them correctly.
Properly fitted shoes are the best defense against blisters on feet. The doctor may recommend foam inserts to make shoes feel more snug without creating more friction, or other protective padded products and gels/creams to relieve the pain often associated with foot blisters.