As the mistake was carried out through the god Indra, he grants Hanuman a want that his entire body might be as powerful as Indra's Vajra, Which his Vajra could also not damage him. In conjunction with Indra other gods have also granted him needs: the God Agni granted Hanuman https://hanumanjimandir.food.blog/2024/07/12/the-universal-appeal-of-lord-shanidev/