Hi, dear I have gone through your question. I can understand your concern. You have gone for blood donation. There may be some technical error in inserting needle in your vein. It leads to extravasation of blood in surrounding tissue which leads to hematoma formation. It will heal gradually within few days. You can apply ice massage for rapid recovery. It has no relation with your blood disorders. No any testing or treatment is required. Just be relaxed. Hope I have answered your question, if you have doubt then I will be happy to answer. Thanks for using health care magic. Wish you a very good health.