If you're trying to reinstall Tot Mini and see PURCHASED greyed out in the App Store on your iPhone, that's because you need to reinstall using the App Store on your Apple Watch.
 

On your watch, find the App Store app in the grid or list view, then launch it. At that point, you'll see a search field at the top where you can type or dictate a search. We suggest using "Iconfactory" because it's less likely to have dictation errors.
 

After you locate the app, tap the icon with the cloud & arrow to reinstall.