For people who have super long periods

Angel
I have my average period for a week and a half and the highest that you can put is 8 days and I want to keep this correct because when I need to I have to show my doc everything and she just sees its on average 8 days rather than a week and a half so is there a way to update this or a way that I can change it to the correct amount of days that would be really helpful thanks 😊