Text messages

If you're using iCloud Syncing for Messages, once you delete a message it's gone.

If you're not using iCloud Syncing and you have a back up that contains the messages, you can restore your phone from that back up. Note that restoring the phone will overwrite everything currently on it.

Restore your iPhone, iPad, or iPod touch from a backup - Apple Support

kelci04 wrote:

How do I know if I’m using iCloud syncing for messages?

See here:

Use Messages in iCloud - Apple Support

what does overwrite everything currently mean exactly?

It means everything that is currently on your device will be erased and replaced with the back up. In effect, your phone's content will go back in time to whenever the back up was done. If it was just done a few hours ago, this may not be a big concern. If it was done days or weeks ago, you'll lose any thing you've added to the phone since then, including messages you've sent or received since then.