Should I Be Concerned For A Head Injury Post Multiple Sclerosis?

HI, i just hit my head under my stairs. It was a hard hit. the area i hit it on is swollen and it is a bit painful. Do i need to get it checked at a doctor? I am ohterwise alright. I also have Multiple sclerosis. I also have this question? I have a dent in the middle of my head. It has been there for a few years, sometimes it is more sensitive then other times. What can this be? So that is two questions.