What can i do about this belt buckle problem?

Yesterday afternoon I was in my brothers room, I bent down on the floor and his belt buckle hook went in my knee all the way.. i pulled it out and put proxide and there was no infection but my leg hurts as though I sprained it.. The belt buckle went in my knee below the bone. I cant walk or move it very much. My friend brought me crutches and i am now using them... please help me figure out what happened .. or whats happening.. should i go to the doctor?? BY THE WAY, THE BELT BUCKLE HOOK LOOKED LIKE THIS, a href="http://www.google.com/imgres?imgurl=http://ny-image1.etsy.com/il_fullxfull.44311605.jpg&imgrefurl=http://www.etsy.com/view_listing.php%3Flisting_id%3D17139829&usg=__FNBW7J_opofkwKWiwK3ggEyjzBI=&h=1125&w=1500&sz=347&hl=en&start=0&zoom=1&tbnid=5Ywc-zq3oIRiRM:&tbnh=146&tbnw=195&ei=o_qZTYWXBNLWiAKuyqSdCQ&prev=/images%3Fq%3Dbelt%2Bbuckle%2Battachment%2Bhook%26um%3D1%26hl%3Den%26biw%3D1280%26bih%3D604%26tbs%3Disch:1&um=1&itbs=1&iact=hc&vpx=233&vpy=98&dur=4136&hovh=194&hovw=259&tx=112&ty=82&oei=o_qZTYWXBNLWiAKuyqSdCQ&page=1&ndsp=18&ved=1t:429,r:1,s:0" rel="nofollow"http://www.google.com/imgres?imgurl=http…/a (THE LITTLE CURVED THING)