<s>[INST] During a normal blood draw I had an immediate sharp pain in the upper part of by arm, from approximately one inch below the needle insertion to approximately one inch above my wrist. When the needle was removed the burning subsided but an hour later there is still slight residual pain. I am not concerned but curious as to why this happens. I had this happen several years ago when I donated blood regularly. Could it be from scar tissue? [/INST] Hellos per the description of your clinical symptoms it seems that there had been mild injury to the nerve which is in anatomical relation to the vessel where needle was inserted. As the symptoms subsided automatically the nerve injury was Neuropathic type, this is mild degree of injury and self limiting. The main neuronal supply of the upper limb is through Radial, Ulnar, Median nerve or their branches. The involved nerve depends on the site of injury. If symptoms persist for long I would suggest you to visit your doctor (Nanomedicine or Neurosurgeon) for further evaluation and management. Thank you. </s>