As the error was accomplished by the god Indra, he grants Hanuman a want that his human body would be as robust as Indra's Vajra, and that his Vajra might also not damage him. In addition to Indra other gods have also granted him needs: the God Agni granted Hanuman https://www.tumblr.com/hanumanmandiradelaide/762919785200762880/fostering-community-and-culture-at-the-hindu?source=share