Log into the account you closed first
Enter your username password
In the first place, there is a warning that you can take it back 30 days. However, if you want to take it back in more than 30 days, you will be asked to press the deactivate button. So it means cancel the deletion.
In other words, there is no such thing as deleting an account permanently, only closing your account, and when you close it, you think it will not be taken back. But since tiktok is not like Facebook, it can be activated whenever you want.