I asked ʿAisha about treating poisonous stings (a snake-bite or a scorpion sting) with a Ruqya. She said, "The Prophet ﷺ allowed the treatment of poisonous sting with Ruqya." (Using translation from Bukhārī 5741)   

«رُخَّصَ رَسُولُ اللهِ ﷺ فِي الرُّقْيَةِ مِنْ كُلِّ ذِي حُمَّةٍ»  

[Machine] "O Messenger of Allah, is there a remedy for scorpion stings?" The Prophet ﷺ said, "Whoever is able to benefit his brother, let him do so."  

يَا رَسُولَ اللهِ أَفِي الْعَقْرَبِ رُقْيَةٌ؟ قَالَ النَّبِيُّ ﷺ «مَنِ اسْتَطَاعَ أَنْ يَنْفَعَ أَخَاهُ فَلْيَفْعَلْ»