Make-up lessons are left to the students (or parents) own discretion. However, when learning an instrument practice and consistency is what counts. I will do all I can to be flexible in my schedule to allow for vacations, emergencies, etc., but a good effort is expected of the student to attend all the weekly lessons.
If you feel unprepared for your lesson, it is still better to attend. You probably have forgotten what was covered in your previous lesson and need to review for the up coming week of practice. It is better to review than to incorrectly practice. This is the number one factor in hindering your playing ability and in causing unwarranted practice frustration.