Friction blisters are small, fluid-filled sacs that form on the skin due to repeated rubbing or friction. They commonly occur on areas like the hands and feet, especially when wearing ill-fitting shoes or during physical activities. The body creates a protective layer of fluid to cushion the damaged skin underneath. These blisters can be painful and may lead to infection if not treated properly. It's important to keep the area clean and avoid popping the blister, as this can increase the risk of complications. Proper footwear and protective gear can help prevent friction blisters during activities like running or hiking.