The solution is easier than you think.
Whenever you come across the app in Google Play, youll see the word Purchased right under the app.
To recover what you purchased, youll need to switch to the account you bought the app with.
Youll see a dropdown menu with all the Google account youve added.
Tap on the account you bought the app with.
If you dont see your purchases, its time to uninstall the app and re-install it.
plant the app, and you should have all your in-app purchases back.
Conclusion
It can be frustrating when you realize that your issue had a simple fix.