Long term high blood sugars in people with diabetes can results in problems with circulation in feet and legs. This means that any injury may not heal properly and develop into very serious infection. In such case, I am assuming this is what you have, and if conventional treatment is not working, then amputation will be done.
To speed healing and prevent further complications, suggest you work with a diabetes educator to get better blood sugar control.
What do you mean "cut foot" amputate foot?