The shapes of round face and oval face are determined by individual genetic factors, bone structure and muscle state. Generally speaking, a person's face is relatively stable after adulthood, and there will be no obvious changes. So it is not common for a person's face to change from a round face to an oval face.

If a person's face has changed obviously, it may be due to one of the following reasons:

1. Skeletal development: In the stage of human growth and development, bones will change. If a person experiences changes in bone development within ten years, it may lead to changes in face shape.

2. Diseases or operations: Some diseases or operations may affect the structure and shape of the face, leading to changes in the face shape.

3. Muscle condition: Muscle movement and tension will affect the face shape. If a person's muscle condition changes within ten years, it may lead to a change in face shape.

Moreover, there is no scientific basis to support the obvious shape change of a person's face just because it has been lost for ten years. So, if you hear the story that someone's round face turned into an oval face, it may be caused by other factors, not just time.

Please note that my answer is general, and the specific situation may vary due to unknown factors such as individual differences. If you want to know the facial changes more accurately, it is recommended to consult a professional doctor or an expert in related fields.