I Had A Fistula Put In Back In August Of

I had a fistula put in back in August of last year. The surgeon clipped a nerve during the surgery. I know this because I felt.my hand go numb during the surgery. He denies clipping the nerve. Since then, I've had terrible pain in my hand plus I still have the numbness. Recently, I've started having uncontrollable cramps. My fingers will lock up in an awkward position. Tonight, my thumb did it and it was unbelievable pain. If I had the same thing in my left hand, I might believe it's carpal tunnel but I don't. I've spoken with two of my doctors, who've both kind of shrugged off my issue. I'm in so much pain and don't.know what to do.