Not only can you follow friends in Instagram, you can also write messages with them. There is an icon in the upper right corner that allows you to start a private conversation with a specific person.
If you have now sent a message there, you may want to undo this. Luckily, the message retrieval in Instagram works and we'll show you how to do it exactly:
1. Open Instagram on your Android smartphone
2. Tap the message icon in the upper right corner
3. Tap the corresponding conversation
4. Press and hold the message you want to retrieve and then select "retrieve message" from the context menu - Done!
You have now retrieved an already sent message in Instagram or undone the send status.