A possible concise summary is:
A man who lost his girlfriend to leukemia is reborn to his high school days and tries to confess his love to her. He also gets a system that can help him cure her disease. He faces challenges from a rival and a bully, but he protects and kisses his girlfriend in front of everyone.
Here are the key facts extracted from the text:
1. The narrator forcefully kissed Yu Youyou in class.
2. Yu Youyou had a crush on the narrator for 10 years in their previous life.
3. Yu Youyou was diagnosed with leukemia and the narrator took care of him.
4. The narrator spent all their savings on Yu Youyou's treatment.
5. Yu Youyou passed away, but the narrator was reborn and returned to the year of the college entrance examination.
6. Yu Youyou was 17 years old at that time.
7. The narrator had a second chance and decided to confess to Yu Youyou.
8. The class teacher scolded the narrator for getting 18 points in the Chinese test.
9. The narrator was accused of molesting Yu Youyou by the class monitor.
10. The narrator was given a task by a system to reach 10 points of close contact with Yu Youyou.
11. The narrator practiced shooting with Yu Youyou in physical education class.
12. Yu Youyou was not good at sports due to his leukemia.
13. The narrator had a basketball competition with another student and won.
14. Yu Youyou treated the narrator to a meal at noon as promised.
15. Li Weiwei, the school belle, bullied Yu Youyou and claimed the narrator as her own.
16. The narrator defended Yu Youyou and sprayed Li Weiwei with Coke.
17. The narrator declared Yu Youyou as his girlfriend in front of everyone.