Painful blisters are fluid-filled pockets that form on the skin, often caused by friction, shear and pressure. These blisters can occur on the feet as a result of ill-fitting shoes, excessive rubbing, or repetitive motion. The fluid within the blister can cause discomfort and interfere with walking or other activities. Treatment may involve carefully draining the blister, applying protective dressings, and addressing the underlying cause to prevent future blisters. It's important to seek professional care if blisters are severe, recurrent, or if signs of infection develop.