How can I retrieve a deleted iPhone message?
I accidentally deleted a very special message on my phone ! How may I get it back?
[Re-Titled by Moderator]
Well, there are a lot of unknowns in your question.
Perhaps "Retrieve Deleted Messages in a Conversation" would work.
Delete messages on iPhone - Apple Support
Or perhaps restoring from a recent backup would work.
Or perhaps the article linked above your post would work