Hello, It is possible (with any trauma be it high energy or low energy) that you could have had a fracture (probably tiny). Maybe after examining you, the health care professionals did not deem it necessary to demand an x-ray. Now, if you are developing bulging and pain beneath the area of scar, it is mostly like be an abscess (boil) developing due to infection as there is a previous breach of skin which would predispose to easy attend by common germs. So the advice is to visit your doctor for evaluation. Antibiotics and antiinflammatory could resolve the situation easily if it is an abscess. If it collects into pus, it might need to be excised and drained for better healing. I will also advise an X-ray to rule out any possibility of an infected neglected fracture (osteomyelitis). Hope this helps