As the error was carried out via the god Indra, he grants Hanuman a want that his system could be as potent as Indra's Vajra, and that his Vajra might also not harm him. In conjunction with Indra other gods have also granted him wishes: the God Agni granted Hanuman https://daltonlifyx.blogzet.com/not-known-factual-statements-about-hanuman-51785291