Take note of the things that can lead to the loss of your TikTok messages when you do not voluntarily delete them.
Majorly, deleting your messages mistakenly and registering your account afresh or recovering your account after it has been banned can lead to the loss of your messages.
So, be cautious when carrying out actions on your phone to prevent accidentally deleting your messages and ensure that you refrain from activities that can lead to the ban of your account.
However, it is important to back up your data should in case you need to recover your messages.