How do I recover a deleted message off of Facebook Messenger

If you are talking about facebook messenger then there is facebook data files from there you can get your messages back
You can download your own archive of this data from Facebook. Here's how:

• Go to Facebook.com/settings
• Tap "Download a copy of your Facebook data."
• Tap "Download Archive."
• It might take a few minutes, but Facebook will alert you when your archive is ready.
• When it is, click "Download Archive" again, and a zip file will download to your computer.
• Browse through that archive by opening each file inside the folder.

https://www.cnbc.com/2018/03/23/how-to-download-a-copy-of-facebook-data-about-you.html

https://www.wikihow.com/Delete-Messages-on-Facebook-Messenger


How to Delete Messages on Facebook Messenger

There are possible ways on how to retrieve those deleted Facebook Albums. In times like this, you need a professional program to help you get those important conversations back. The easiest and fastest way to retrieve those deleted Facebook Albums is through third-party software. FoneDog - iOS Data Recovery is the world's leading iOS recovery program that has helped millions of users around the globe. It has the highest retrieval rate in the industry and works with all iOS devices such as iPhone, iPad and iPod Touch. To begin the deleted Facebook Albums recovery, follow the simple steps below:
Option 1.The three-party application for restoring deleted messages
Step1. Run FoneDog - iOS Data Recovery after download and installation

Step2. Click "Recover from iOS Device" from the left-side panel tool options
Step3. Scan and Recover Facebook messages from iPhone Completely
More refer:
How Do You Retrieve Accidentally Deleted Text Messages from iPhone 7 or iCloud Backup
How to Recover Deleted Viber Messages from iPhone 7/ 7 Plus
Hope it can help you sooner

GT Recovery for Windows Download: http://www.gtrecovery.net

We use Facebook daily to do conversation with our friends, relatives and sometimes with our profession clients too.

It's very important for us to get those conversations back if mistakenly they can deleted.

Some common situations that lost Facebook private messages you can recover from:
1). accidentally deleted it on your android phone
2). lost messages after Android 5.0 updated or other Android upgrade.
3). save messages from water damaged, crashed, broken or smashed Android phone
4). Android delete facebook messages randomly by itself
5). Factory restore Android phone.

We use Facebook daily to do conversation with our friends, relatives and sometimes with our profession clients too.
It's very important for us to get those conversations back if mistakenly they can deleted.
Some common situations that lost Facebook messages you can recover from:
1. accidentally deleted it on your android phone
2. lost messages after Android 5.0 updated or other Android upgrade.
3. save messages from water damaged, crashed, broken or smashed Android phone
4. Android deleted messages randomly by itself
5. Factory restore Android phone.
And more...
Watch this video and share it with your friends too so that they can also get their precious lost data back.

Unfortunately, Facebook currently lacks the ability to recover deleted messages. Once they are deleted, they are effectively gone.

Perhaps in the future, Facebook will add that feature but for the moment what is deleted is gone.

There is a way of recovering deleted facebook messages.
In order to recover a facebook conversation:
You must receive email notifications from facebook, telling you when someone sent you a message. Ex. Paul Wilson sent you a message on facebook
Click on that link.. If you have already deleted the notification, go to your deleted messages inbox (hotmail)..
(It's impossible to completely remove something from a computer!)
At the bottom of the message, you will see a link, click on the link that says :
To reply to this message, follow the link below :
ex. http://www.facebook.com/inbox.php?lh=0e5633de8d92e7fab7145ffc710260dc&
then click on : SHOW DELETED THREAD.
Done!

There is a way of recovering deleted facebook messages.
In order to recover a facebook conversation:
You must receive email notifications from facebook, telling you when someone sent you a message. Ex. Paul Wilson sent you a message on facebook
Click on that link.. If you have already deleted the notification, go to your deleted messages inbox (hotmail)..
(It's impossible to completely remove something from a computer!)
At the bottom of the message, you will see a link, click on the link that says :
To reply to this message, follow the link below :
ex. http://www.facebook.com/inbox.php?lh=0e5633de8d92e7fab7145ffc710260dc&
then click on : SHOW DELETED THREAD.
Done!
Hope this helped
Dr Reed