Check the chat on the other person’s account if they still have the messages
Review your Instagram data download for message history
Check connected email notifications or message alerts if enabled
Look in your phone’s notification history if message previews were saved
Restore from a device backup if your phone backup includes Instagram data
Check if the messages were only archived or hidden, not deleted
Use Meta Accounts Center to request and download your information
Contact Instagram Support if you believe the deletion was accidental or unauthorized