Sayyiduna Abu Rimthah (may Allah be pleased with him) said: I went with my father to the Messenger of Allah (peace and blessings be upon him), and I saw something like an apple on his shoulder. My father said to him: I am a physician; shall I not lance it? He (peace and blessings be upon him) said: "Its physician is the One who created it."
Hadith Referenceالمعجم الكبير للطبراني / باب الياء / 18922