As the mistake was performed from the god Indra, he grants Hanuman a wish that his physique will be as solid as Indra's Vajra, Which his Vajra might also not hurt him. In addition to Indra other gods have also granted him wishes: the God Agni granted Hanuman a want https://www.tumblr.com/hanumanmandiradelaide/762919785200762880/fostering-community-and-culture-at-the-hindu?source=share