I don't know how to get it back.

I can't get it back. According to Red Star News, as of August 4, 2023.

1, the flash message cannot be viewed, which is different from the ordinary message received. Ordinary messages will be saved directly after they are received. As long as you click the SMS function on the mobile phone, you can see all the message records, but as a flash message that can be directly displayed on the screen of the mobile phone, it cannot be retained.

2. That is, after the mobile phone receives the flash message and clicks Close, the record of the flash message cannot be found on the mobile phone, and the information will not be automatically saved after reading. You must click OK before you can perform other operations on your phone. This form of burn after reading is enough to ensure the security of information transmission.