I Had A Trama Head Injury During A Small Vender

I had a trama head injury during a small vender bender, the impact threw me upward and I hit the left side of the top of my head on the visor bar, I went er had scan done said I was fine and sent me home, I have since developed a severed sharp pain on that side of my head, it comes and goes now and again, cud it be a blood clot that is drawing fluid and causing swelling, (I jst read this for head trama and headaches). should I be concerned....im scared! Eva