FALLUJA, Iraq (CNN) -- "I can still hear her screams," says Mohammed Rasoul, pointing to the sidewalk where he was sitting moments before a car bomb ripped through his street, killing his younger cousin and blowing off his right leg.
Mohammed Rasoul stands at the grave where his cousin is buried. He lost his right leg in the attack that killed her.
Mohammed, now 14, shudders as he stands on the street he grew up on in the war-torn city of Falluja. He admits he's afraid of another explosion.
CNN first met Mohammed two years ago. Every day, on crutches he would make the painstaking journey to his cousin's grave to water a small tree he planted next to it. She was just 6-years-old when she was killed in the car bombing on October 13, 2006.
Mohammed's story came to the attention of the Global Medical Relief Fund, a U.S.-based charity that helps children in war zones across the globe. Within months, Mohammed and his mother, Jinan Mohammed, were on their way to the United States, an experience that changed their lives and their perspectives. Watch Iraqi amputee walk again »
"Before I went to America, the only America I knew was the one that harmed us, destroyed our homes and our lives," his mother says. "But when I went to America, I saw such kindness and humanity."
At the Shriners Children's Hospital in Philadelphia, Pennsylvania, Mohammed was fitted with a prosthetic and for the first time in two years, his mother saw her son stand on his own. Her eyes immediately swelled with tears. She had not realized how tall Mohammed had gotten since the attack. Meet other children helped by the Global Medical Relief Fund »
"My son's life changed," she says, back in Iraq nearly a year after her son's treatment. "He used to be so depressed. He would watch boys playing football, and he would be balancing on one leg on the sidelines. Now, he walks tall and proud."
When they came back to Iraq, there were celebrations for days. Everyone wanted to see Mohammed walk, and everyone wanted to know what America was like.
"Everyone was so happy," Mohammed remembers. "They were just staring at me because they couldn't believe that I was walking."
But having experienced life in America -- a life without fear -- coming back to Falluja, where most of the buildings still bear the scars of war, was a traumatic reality check. His overwhelming fear of another attack came back, even stronger than before.
"I am afraid," he says. "I feel that people are pointing at me saying, 'Look, he was in America!' And, you know, here people get killed for that."
He adds, "The worst day of my life was when I returned to Iraq."
Despite his fears, he still makes the daily trip to his cousin's grave. He waters the tree -- now just a twig after somebody snapped it in half -- and prays for his cousin's soul and for his own. His only wish is to leave his country and get past the painful memory of what he has endured.
"After what I suffered through here, no, I won't ever miss Iraq," he says. "This country is over. Iraq will never return as it was."
Mohammed has now returned again to the United States with the help of the Global Medical Relief Fund. He's outgrown his prosthetic and will soon be fitted with a new one.