As the mistake was carried out because of the god Indra, he grants Hanuman a want that his physique can be as potent as Indra's Vajra, and that his Vajra also can not hurt him. Together with Indra other gods have also granted him needs: the God Agni granted Hanuman https://hanumantempleinadelaide.fitness.blog/2024/06/14/discover-the-essence-of-hinduism-at-the-hanuman-mandir/