What is the ruling on striking someone who verbally assaulted me, in order to preserve dignity and prevent others like him from overstepping, especially if he is younger than me or around my age?

It is not permissible to retaliate against injustice with more than what originated from the oppressor, based on the Almighty’s saying: "And if you punish [an enemy], then punish with an equivalent of that with which you were harmed." So, if one person insults another, it is not permissible for the insulted person to strike him; rather, he may return the insult in kind, though forgiveness and pardon are preferable. It is not permissible to transgress in retaliation by exceeding the limits of Allah, so do not lie about him even if he lies about you, for disobedience is not met with disobedience.