Musnad Ahmad 32:254

Waki' narrated to us, Sufyan narrated to us, from 'Asim al-Ahwal, from Yusuf, from Anas, who said: "The Messenger of Allah, peace and blessings of Allah be upon him, granted a concession regarding Ruqyah (incantations) for the evil eye, the Namlah (a type of skin sore or ulcer), and the Hummah (venomous sting)."