Calculate how many days since last migraine

Hi everyone, I'm trying to calculate how many days I've been free of a migraine since I last pressed a button(migraine over button) I've tried before coming on here so please help. Thanks in advance.

Use a TinyDB tag LASTMIGRAINE to hold the Clock1.SystemTime of the last migraine, or 0 if none yet.

In your Migraine Button .Click event, subtract TinyDB tag LASTMIGRAINE value from Clock1.SystemTime to get milliseconds from last migraine.
Turn that into days using division by (how many milliseconds are in a day)
and display it.

Add a Save button to save current Clock1.SystemTime in that TinyDB tag.

Thank you so much, is there any chance I can be a pain and ask how that would look in block format as I'm still fairy new to coding and app inventor. Thank you again for the help

This one has been asked many times. Try searching the community:
You will find some blocks examples to help you.