Prior to any changes being sent to the database you will see a preview in the bulk edit grid. Once you click on the “Save Changes” button the products will be updated. There isn’t a reset option just like there isn’t for editing products directly within WooCommerce.
If you need to roll back a massive change you may need to contact your hosting provider about restoring from backup. If you have received any orders since the backup that could be problematic though, you may need to manually process the orders and reset the Order #.