In a video released by the Brazilian football confederation on Saturday, Neymar thanked fans and everyone else for the support in this "very difficult moment."
"I don't have words to describe what has been going through my head and my heart," said Neymar, trying to stay upbeat but still sporting a subdued look on his face. "I just want to say that I will be back as soon as possible. When you least expect I'll be back."
Wearing a black T-shirt and a black hat turned backward, he spoke in a low tone of voice, his eyes still heavy.
"My dream is not over yet," he said. "It was interrupted by one move, but it will continue and I'm certain that my teammates will do whatever possible so I can fulfill my dream of being a champion. I won't be able to fulfill the dream of playing in a World Cup final, but I'm sure they will win this one, they will become champions, and I will be there with them, and all of Brazil will be celebrating together."
It was the first time Neymar had spoken publicly since fracturing a vertebra late in Brazil's 2-1 win over Colombia in the quarterfinals on Friday.
The video was made just before the striker was airlifted from Brazil's training camp in a medical helicopter to be treated at home for the back injury that ruled him out of the last two games of the World Cup.
Brazil doctor Jose Luiz Runco guaranteed the injury will not have long-term effects on Neymar's career and said the player could even travel to Belo Horizonte to watch the semifinal against Germany on Tuesday if he is not feeling a lot of pain.
Runco said he believes Neymar can return to action in about 45 days, and that Barcelona doctors were informed of the player's conditions from the beginning.
"He was extremely moved when I gave him the news that he was out of the World Cup," Runco said. "He cried a lot, which was a natural reaction at that moment. But I told him that although his dream was being cut short, he was still a 22-year-old with a lot in front of him. It was still a 'good' type of injury."
Neymar was on a stretcher when he was transferred from an ambulance into the helicopter that took off Saturday afternoon from one of Brazil's practice pitches in the city of Teresopolis, about an hour from Rio de Janeiro.
Sports channels broadcast live as Neymar - who is a star on the field and a celebrity off of it - waved briefly from his stretcher inside the helicopter before the doors were closed and the aircraft flew away.
Medical staff spent several minutes securing the Brazilian striker inside the helicopter as his father and the president of the Brazilian football confederation, Jose Maria Marin, watched closely.
Brazilian President Dilma Rousseff published a letter of support to "a great warrior."
"Your expression of pain on the field yesterday (Friday) hurt my heart and the hearts of every Brazilian," she said. "I know that as a Brazilian you never give up, and sooner than expected you will be back filling our souls with happiness and our history with success."
Several players and many Brazilian celebrities also showed their support to the Brazilian star through social media.
Neymar had flown back to Rio de Janeiro with the rest of his Brazil teammates after the match in Fortaleza, then rode in an ambulance the rest of the way to the team's training camp in Teresopolis.
When the plane arrived in Rio early Saturday, teammates came one by one to embrace him as he sat in a wheelchair waiting to be taken into the ambulance.
The 22-year-old Neymar broke his third vertebra after being kneed in the back by Colombian player Juan Camillo Zuniga in the 86th minute at the Arena Castelao.
Neymar was carried off the field in tears on a stretcher and "screamed in pain in the dressing room" before being taken to a hospital for tests, the Brazilian confederation said in a statement.
Neymar had been one of the standout players of the World Cup, scoring four goals in the team's first three games.
Fans attending both of Saturday's quarterfinals chanted Neymar's name several times.