You should ask Facebook about that. Regrades :)

Try this may be you get your all messages, you have got email saying that you have got messages.Fine the email, click the link at the bottom of email, which brings you to facebook and the message center. Under the message , it will show you the deleted messages . Then, you will get show … Read more

No, unfortunately you cannot retrieve deleted messages from Facebook.

• Facebook does not store your deleted messages once you have selected them to be deleted.

Under the privacy act it is illegal for companies to store information you have requested to be removed. This means that sites such as Facebook have to remove the … Read more

I doubt you can...it's like if you send a sms(you know you can't cancel it!) so  it works the same with the inbox messages!