"Made up" means "invented". I think the term used is "make up class". You take it to "make up the time you missed yesterday" or "make up for the class you missed yesterday".
I don't know if it's used in British schools though. When I went to school in the UK, such a class did not exist. If you were off sick and missed classes, you had to ask your classmates what you had missed but you generally weren't expected to do the homework that was set on the day you were absent. If such a class exists now, it's probably a "catch-up class" in BrE.
Student or Learner