Check the progress on the new database you've provisioned.
Restore the database
heroku pgbackups:restore DATABASE_URL
Point to the new database by promoting it.
heroku pg:backups:promote DATABASE_URL
Re-instate the app by turning off maintenance mode.
Double check your work.
Measuring the Health of Your Database
There is a tool called PG Extras that can help you measure the health of your database and application. It can give you insight on things such as load time, database usage, long queries, etc. Here are a few commands I use regularly.