The Messenger of Allah ﷺ used to have himself cupped on the top of his head and between his shoulders, and that he used to say: If anyone pours out any of his blood, he will not suffer if he applies no medical treatment for anything. (Using translation from Abū Dāʾūd 3859)
أَنَّهُ حَدَّثَهُ أَنَّ نَبِيَّ اللهِ ﷺ كَانَ يَحْتَجِمُ عَلَى هَامَتِهِ وَبَيْنَ كَتِفَيْهِ وَيَقُولُ مَنْ أَهْرَاقَ مِنْ هَذِهِ الدِّمَاءِ فَلَا يَضُرُّهُ أَنْ لَا يَتَدَاوَى بِشَيْءٍ أَظُنُّهُ قَالَ لِشَيْءٍ