Painful Lump on forehead. Diagnosis too.

My mother hurt herself in the forehead about 1 year back by banging into one of the wooden doors at home. At that time she had pain, swelling and bruising in the forehead just above the right eyebrow. The lump originated at that time but over the course of time it got suppressed and vanished on its own. Recently, about a week back, the lump resurfaced and has become really painful. Unfortunately, we're not even sure of which specialty to approach for this. Since the original injury was related to bones, posting this question under the same category. Please suggest the right specialty to approach for this and also the best course of action with some probables of what kind of diagnostic tests are required and a probable diagnosis too. Thanks.