It may be annoying if you are missing important messages on Facebook. If you delete a message on Facebook you should be careful while doing so because if it gets deleted permanently you may not get it back at all. You may ask however for the copy of the same message from the one you had sent these messages to. If he/she still has those messages intact then you can easily recover deleted Facebook messages. However, if you want to recover deleted Facebook messages then you can follow the below steps on your iPhone:

How To Recover deleted Facebook Messages On iPhone?

1. Open the Messenger app on your iPhone.
2. Now tap Home and then in the search bar type the keyword text if the deleted or lost message. You will see a search bar on top of your screen.
3. As you see deleted messages as a search result, you can select it and then restore it to your iPhone.

How To Recover Deleted Facebook Messages On android?

You can follow the below steps to recover deleted Facebook messages on Android. If you have your messages archived in the Facebook messenger app on your android device then you can recover permanently deleted messaged on Facebook messenger.

1. Open the Facebook messenger app in your android device.
2. Go to recent conversations.
3. Now you can click in the search bar and type the text to search the conversation that you previously archived.
4. As you see the message you are looking for then you can select it and press the Unarchive Message option to unarchive your message.

This is how you can retrieve deleted messages on Facebook chat. 

 How To Archive Facebook Messages on iOS?

You can follow the below steps to archive Facebook messages on IOS;

1. On your IOS device tap the Facebook Messenger app to open it.
2. Now you need to select the "messages" tab here.
3. Now in order to archive messages, you need to locate them.
4. Now you can select that message or messages you want to archive.
5. Now once you have selected all such messages you can tap "Archive" to send these messages into the archives. Once your messages are sent to the archives they will be deleted from your list of messages. 

So, if later on, you want to retrieve deleted messages on Facebook chat you can do it from your archived messages by unarchiving them.