Once you are diagnosed with type 1 diabetes, insulin is your best friend forever.
As you start injecting, you’ll be asked to keep rotating your injection sites. If you keep injecting on the same site over and over again, there will be either build up or break down of fat under the skin called as lipodystrophy or lipoatrophy ( either lumps or indentations on the skin). This further causes thickening of skin, which lacks nerves in it resulting in painless injections and eventually hampered insulin absorption.
So , it is always recommended to rotate your injection sites either clockwise or anti-clockwise so as to give it time to recover before being used again.