Normally the purchase should appear in the game instantly. If that didn't happen, please exit the game, make sure that you are properly connected to the Internet, and log back in. A fresh connection with the server may speed up the process.
You might have to restart the device as well!
If the purchase does not appear, please contact us using the Customer Support option in the game, attaching the purchase confirmation (screenshot of the confirmation email from Apple Store or a screenshot of your purchase history), so we can confirm whether the transaction appeared on your account or not.