Removing the “unread messages” indicator when messages were deleted by bug

So, I recently experienced what seems to be quite an old bug in the default Messages app for the iPhone: while I was typing a text message, my phone’s battery died, and when the phone was powered back on, my text message history seemed to have been entirely deleted. However, there’s still the little number in a red bubble on the app’s icon indicating unread messages, which I don’t seem to be able to remove since I can’t read the deleted messages. Is there any way to recover the messages so that I can read them (other than using a cloud backup I haven’t made), or a way to reset the unread messages indicator to display the correct value for the messages it has access to?