<s>[INST] A few years ago, I donated blood, from my right arm, and the nurse seemed to insert the needle incorrectly. I had donated before so I was used to the mild discomfort, but this felt unusually painful. I told the nurse that the needle didn t feel right, and she said it was normal. Immediately after donating, my arm swelled and felt immensely painful for weeks. Since then I have a permanent lump near the area. I resorted to donating from my left arm, but today, a different nurse insisted he take from my right arm. I told him the history, but he shrugged it off. My right arm is now bruised and the lump is throbbing. It gets sensitive every now and then, but the blood donation aggravated it. What is the lump or the cause of it and should I get it checked out? [/INST] Hello there! Blood donation resulting in lump. Can be connected if that is a throbbing and pulsating. It seems like a hematoma and yes MIS directed needle cases that. So I want you to seek help and have a Doppler duplex sonography of the limb to see what's with the vasculature also do the bleeding profilelike platelets, PT APT INR to rule out bleeding tendencies. And stop donating blood like Halloween candies. You can maximum and should donate once every quarter year. No more than 4 times at most. Good Lucks Khan </s>