1. First, write a formal email or short message to the teacher, introduce yourself and explain your purpose. You can mention that you have attended the teacher's class, which shows that you are interested in this class.

2. In the letter, express your respect and gratitude to the teacher. Thank you for your support and guidance in your study, showing that you admire and benefit a lot from your teacher's teaching work.

3. Then, make your request. It shows that you have high expectations for this course. I hope the teacher can consider your performance and improve your score. You can mention your efforts and achievements in this course and point out that you don't think this achievement fully reflects your performance.

Finally, thank you again and end politely. Thank the teacher for his time and consideration, and explain that you are looking forward to hearing from the teacher.

It should be noted that when asking for a higher score, you must be polite and respectful, and don't use offensive or threatening language. At the same time, we should abide by the rules and regulations of the school and not violate any rules and regulations.