The huge disfigurement was sprouting from the centre of her lower jaw bone and was formed by cells that usually make the enamel of teeth.
Miraculously the teenager was still able to eat and speak, but became so self-conscious that she stopped going to school.
After local hospitals failed to help, Grace was admitted to charity hospital Mercy Ships, where she underwent a four-hour surgery to remove the tumour, lower jaw and teeth.
Grace said local doctors offered no treatment because they remained baffled by her condition.
“It started from a little swelling inside and the gums started growing little by little,” she said.
“We went to hospital and they didn’t know what it was – they did nothing.”
Grace’s mother Christine says she was forced to watch her daughter suffer and had no idea who to turn to for help.
Christine said: “I didn’t know what to do – in hospital they just talked a lot but did nothing.”
Describing what it’s like to live with a life-threatening tumour, Grace said: “I was sick, I was always indoors, I was not happy anymore, I worried all the time.”
Eventually the young girl was discovered by a Christian pastor who campaigned to get her medical help.
After posting the teenager’s story on the church website, a reader told them about Mercy Ships.
Mercy Ships operates the world’s largest floating hospital named the Africa Mercy – a converted Danish rail ferry – providing free healthcare services to some of the neediest people in the world.
Sixteen hundred volunteers, including doctors, nurses and teachers from around the world, provide their time for free each year.
Once onboard the ship, Grace was given a CT scan to allow surgeons to see the tumour and plan the surgery necessary to remove it.
Surgeon Dr Gary Parker said: “When it grows where it is in the mouth – as it expands it pushes the tongue into the back of the throat and that’s when they get into airway crisis where they can’t breathe.
“Ultimately if she wasn’t treated she could die from suffocation.”
During the risky surgery, the bottom of Grace’s jaw and her teeth had to be removed along with the giant tumour.
Dr Parker added: “To remove the tumour we had to open the neck to allow access to the jaw and separate the tumour from the normal jaw.”
After removing the football-sized lump Dr Parker replaced the removed jaw with metal plates made of titanium.
In six months time Grace will be offered artificial teeth – when she has fully recovered.
That will help her with her chewing – appearance-wise and functionally she should be able to have a normal life,” Dr Parker added.
Grace’s life has been completely transformed by the surgery. With her new-found confidence, the teenager can now look to the future.
She hopes to study medicine and pursue a career in nursing so that she can help others with complicated medical conditions in the future.
Grace said: “They made me happy – now I want to study and help other people.
“I would like to work on the Mercy Ship to help people for free, like they have done for me. It made a really big change because of the way my face was.
“It changed my life – now my face is good.”
