As the mistake was carried out from the god Indra, he grants Hanuman a desire that his human body will be as robust as Indra's Vajra, and that his Vajra can also not hurt him. In conjunction with Indra other gods have also granted him wishes: the God Agni granted https://elbertk418zbb7.ageeksblog.com/31787334/everything-about-panchmukhi-hanuman