have a hide like a rhinoceros
To have the ability to ignore verbal attacks or criticism from others. If you're going to pursue a career in politics, you need to have a hide like a rhinoceros and not let criticism bother you.
have a hide/skin like a rhiˈnoceros
(informal) be tough and not easily offended; have no fear of criticism from others: Say what you like about him, he won’t care; he’s got a skin like a rhinoceros.