Hi, The pain in the arm after such a procedure could be attributed to the following; 1. It could be a hematoma cause by a ruptured vein resulting from the repeated tries by the nurse which would increase the chances for the vein to rupture. A hematoma is a collection of blood that forms outside the vein. You might notice that the surrounding area around a hematoma to be red or blue, and the surrounding tissue to become swollen. The body has the ability to reabsorbs such blood collection slowly over time. 2. The second possibility is that while trying to draw the blood the nurse accidental hit a nerve. In this case your friend might also notice other symptoms such as numbness and tingling in the arm or hand. If the nerve that was hit was a large nerve, she might have felt a brief, shock-like pain as the needle nicks the nerve. Fortunately, most venipuncture nerve injuries heal, but it may take weeks or months for the arm discomfort and nerve symptoms to completely go away. In rare cases, the nerve damage can be permanent. It s also helpful to mention here that sometimes the hematoma could be large and causing pressure over the nerve which might cause as well tingling or numbness sensation. I suggest that you review with your friend what did she experienced since the blood donation, did she feel any shocking or shooting pain during inserting the needle? Did she had a swelling around the venepuncture site or something like a bruise? has the pain been the same all along or is it getting better? these questions would help you relate to the actual cause. If the pain persisted or got worse I d highly recommend visiting the doctor to have her arm checked. Hope this helped you understand the condition and I hope she gets better very soon. Dr. R. Hafez