"between your eyes": on top of the head. You say on top of the head, but perhaps (the intent is) literally, "between your eyes"? It is, therefore, written (Devarim 14:1) "Sons are you to the L–rd your G–d. You shall not gash yourselves, and you shall not make a bald spot between your eyes for the dead." Just as there, the top of the head is meant, so, here.