Nothing serious. If it is a grade test, the final grade is 30% of the usual grade+70% of the thesis grade. If you are found to be truant, you will usually be demoted one level, but not more. Each school has different regulations. Generally, truancy accounts for 30% of the total time to cancel the examination qualification.

It's no problem to take the exam once.

Study hard in the university, and it is recommended not to skip classes often.