It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) was cupped while he was fasting, and he gave the cupper his wage; had it been unlawful, he (peace and blessings be upon him) would not have given him a wage.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 13342