Sore in my mouth won't go away!

I have had this cut in my mouth over a year now, its on the tip of my tounge and it turns white colored sometimes! I went to the DR and got antibiotics and it seemed to be helping and then had to go back and get more and i thought it was going away so i never went back. Now its back worse than it was before and i no longer have insurance to go to the doctor! Also my family doctor didnt know what it was and refered me to an ear nose and throat doctor! Does anyone know what it is or what i can do to get it to stop hurting?