HUGE app size, majority is data using up lot of internal storage space

See attached PIC please

Clearly the app is sucking up huge and yet (slowly) increasing internal storage space. This is mainly due to the app's data sucking up enormous and yet (slowly) increasing internal storage space. How do I fix this? Clearing the app's data by using that clear data button there is very risky and seems wrong from the next PIC you get by clicking the button, what it says there.

bump.