As the mistake was done from the god Indra, he grants Hanuman a wish that his body would be as potent as Indra's Vajra, Which his Vajra can also not damage him. In conjunction with Indra other gods have also granted him needs: the God Agni granted Hanuman a desire https://hindutempleadelaide.sport.blog/2024/08/08/gaushala-shewa-a-sacred-initiative-at-hanuman-temple-adelaide/