Every school has a rule that if you miss a certain percentage of classes, the teacher can disqualify you from taking the final exam of the course. The specific proportion defined by each school is different, depending on how it is written in your school's student handbook, which is generally 10% of the total class hours.

If you have been warned by the teacher, don't be absent from class again. If the teacher has clearly told you not to take the final exam, then you should admit your mistake to the teacher. Just like someone upstairs said, just grind soft and hard, and have dinner and give gifts if necessary.