How should I deal with those who mock and ridicule me by saying, "O pilgrim," when I make a mistake, after my return from Hajj?

Praise Allah for the Hajj, and be diligent in acts of obedience and avoiding sins, so that your Hajj may be accepted (mabrur). Remember that a sign of an accepted Hajj is that you become better than you were before the Hajj. Focus on your standing with Allah, not on people's words. Make any taunt or mistake a motivation for repentance and correcting your path.