As the error was accomplished because of the god Indra, he grants Hanuman a wish that his overall body could be as solid as Indra's Vajra, Which his Vajra can also not harm him. As well as Indra other gods have also granted him wishes: the God Agni granted Hanuman https://archerpeqai.theideasblog.com/37517364/the-definitive-guide-to-hanuman