Musnad Ahmad 32:233

Waki' ibn al-Jarrah al-Ru'asi 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 for Ruqyah (incantation) for the evil eye, the sting of a venomous creature, and the Namlah (a skin ailment/ulcer)."