Blisters are the result of recurring mechanical stress. A blister is a deposit of fluid in or under the skin.
Aim to keep blisters intact as long as possible to prevent infection in the area and let the new skin grow in peace. You should cover blisters with a bandage or strip of polyurethane foam that does not stick to the skin and replace the bandage or strip on a daily basis. It's important for someone with diabetes to check the condition of a blister daily to prevent inflammation; for this reason, for example, a blister plaster should also be changed daily.
If a blister bursts and the surrounding area becomes red as a sign of infection, show it to your doctor.
You can use, e.g. talcum powder or a soft protective strip to prevent blisters.