In your current calculation, comment characters cause FileMaker to ignore the first row. Is Team Leader a field name or should this text be in quotes?
I'm guessing that you need this expression:
( Get ( AccountName ) = "Team Leader" and not $$Locked ) OR
(CreationDate > (Get(CurrentTimeStamp)-86400))
Your script would set the variable $$Locked to True to lock out changes by the Team Leader. This allows a user with an account named "Team Leader" to always be able to access the record unless the variable $$Locked is set to true.
If you need the "lock" to take place on a record by record basis, set a field in the record to True and refer to that field in the expression in place of the global variable.