Bloodletting by an Elder
Scholars have said that if one dreams of an elder performing bloodletting on them, it may indicate hearing words from a friend. If blood exits the vein, the dreamer may be rewarded for it. If no blood exits, the truth will be spoken about them, and the bloodletter will be absolved of sin. If the bloodletting is done horizontally, the talk will cease, but if done longitudinally, the talk will increase and multiply.
Per Ibn Sirin's Muntakhab al-Kalam fi Tafsir al-Ahlam