What Causes Pain And Numbness In The Arms?

My sister, Christy, 41, had a blood draw done on Thursday of this past week. She is diabetic and gets this done monthly. Never before has there been pain associated with this process. This particular time was incredibly painful. The tech was rude and told her the pain was due to the blood draw and to stop complaining. Four vials were taken and 3 days later her arm is still hurting. She says that the pain comes and goes. it starts in the inner elbow, where the blood was drawn, and shoots to her fingertips. Her lower arm is still numb, too. She wonders if the tech hit a nerve or something along those lines. She called me today asking if she should go and get it looked at immediately or can it wait as the pain will eventually subside. Thank you for taking the time to look into this for us. ~Amy