Possible Clues:

• PS - it's a paper in hospital for consideration!
• Postscript comes to mind in the end? It's not before time!
• Fatter, possibly eating whilst getting second opinion
• Something added later
• A later addition
• Come to think of it, it's a late addition and it's not the answer you'll come up with immediately
• It's even more daft losing the head by giving a piece of one's mind with additional remark
• Item added later
• A reflection from worried father to thug
• A later idea Mad Hatter fought