Then you can browse all lost messages on your iPhone, including Snapchat messages.
This completely vanishes or disappear the whole conversation.
Clearing your conversation should remove any saved chats.
You actually have to clear the cache of your Snapchat app and on the phone itself, otherwise your chat partner will still be notified that you took a screenshot when you log back in.
Even if you delete or clear the conversation history, the saved messages aren't going to delete.
Select the specified deleted messages, and click on on the Recover button; Wait for some moments and your will messages will be recovered soon.