As the mistake was completed through the god Indra, he grants Hanuman a desire that his system will be as robust as Indra's Vajra, Which his Vajra might also not harm him. Along with Indra other gods have also granted him wishes: the God Agni granted Hanuman a want that https://mynichedirectory.com/listings13292428/not-known-factual-statements-about-hanuman