How can one get rid of the feeling of being different from people and the fear of work or the police due to growing a long beard and raising the izar (garment)? And is punishing oneself for missteps by depriving oneself of pleasures until one repents considered a correct method or not?

The treatment for fears of people when growing a beard and shortening one's garment is through sincerity to Allah and genuinely seeking His pleasure, and by knowing that the path to Allah requires patience and sacrifice. Reliance on Allah suffices for all worries, as He, the Almighty, said: "And whoever relies upon Allah – then He is sufficient for him." Holding oneself accountable and conditioning it are among the beneficial matters for its rectification.