If you have hidden app purchases on your account and would like to unhide them, there are a few different ways that you can go about doing so. One way is to simply sign out of your account and then sign back in. This will unhide any hidden app purchases that you may have on your account. Another way is to go into your purchase history and look for the app that you want to unhide. Once you find it, simply click on the Unhide button next to it and this will unhide the app from your purchase history.