Yes, it is normal to feel a lump under the skin at the injection site when taking fragmin. This reaction can be reduced by injecting in different areas each time and applying cold to the skin a few hours after the injection. If you are experiencing bruising, it may be helpful to review your injection technique with a pharmacist to avoid parallel injections that can cause bruising and swelling. Additionally, injecting into the side of the thigh can be a good alternative.