As the mistake was performed because of the god Indra, he grants Hanuman a want that his entire body can be as strong as Indra's Vajra, and that his Vajra can also not harm him. Together with Indra other gods have also granted him needs: the God Agni granted Hanuman https://bajrangbalisouthindiantemples.blogspot.com/2024/07/the-multifaceted-role-of-hanuman-mandir.html