Higonokami Becoming too Loose

[me∆tgrinder]

Long time lurker, first time poster. I was hoping my first post could be a bit more interesting than this, but I have a question that I really need help with. So, my higonokami has become a favorite of mine since it was given to me for Christmas, but the blade was just loose enough to slightly open if shaken enough. I tried tightening it by tapping on the pin with a ball peen hammer and now it's really loose. It is so loose that if I hold it by the lanyard hole, the blade flies all the way open. No matter how hard I try, the knife's condition does not improve. Is the knife a lost cause or is there someway I could fix it?