Incorrect exercise record in the activity app

I accidentally manually created an exercise for over 800 minutes in one day (I had meant to create one for 10 minutes). I went into the activity minutes and manually deleted each 1 minute exercise throughout the day, so everything is fixed now - except I still have an 800 minute exercise record.

I'd like fix this so that my true exercise record is reflected on the badge, without losing all of my other data.