As the error was completed by the god Indra, he grants Hanuman a wish that his overall body will be as strong as Indra's Vajra, Which his Vajra might also not hurt him. Together with Indra other gods have also granted him wishes: the God Agni granted Hanuman a want https://princedirectory.com/listings13358662/the-fact-about-hanuman-that-no-one-is-suggesting