It is important if you are placed in a cast not to wet the cast. Thus, either after surgery or while in a cast it is recommended that the patient obtain a cast bag that can be purchased in a surgical supply store. This is placed over the arm and prevents water from getting in the interval between the cast and the skin. If this does occur, it is important to immediately dry the area perhaps with a hair dryer or changing the cast and drying it off manually. Water underneath the cast can cause blistering and lead to breakdown of skin and possible infection. In addition to keeping the cast dry and clean, it is important not to put anything inside of the cast such as powder and/or lotion and not to pull the lining out from inside the cast.