What Is The Cure For Constant Lightheadedness, Pressure On The Left Side Of Head And Hydrocephalus?

I had an automobile accident on May 9, 2013. Progressively I have had a constant light headedness and pressure on the left side of my head, where I hit the door jam. There is a numbness on my left cheek from the ear to the chin. My vision at night is extremely blurry, and blurry in the daytime - just not as bad. My family is worried. I went to the ER and they did a CT scan. I followed up with my doctor and he said that there was a slight prominent ventricle that could be hydrocephalus. My doctor said he is not worried because my symptoms aren't bad. I don't have trouble walking and I haven't lost control of my urine. My family is worried at how non urgent the doctors are reacting. I want to know if the lightheadedness doesn't subside when should I consider a second opinion?