John Henry Dundas, 10, was left screaming in pain and covered in blood after a Staffordshire Bull Terrier launched a ferocious attack on him at a house in Intake more than two weeks ago.
His angry mum Natasha has called for the dog to be destroyed and has launched a petition calling on South Yorkshire Police to thoroughly investigate the incident, saying she feels 'massively let down' by their response.
However, the dog is now back with its owner and South Yorkshire Police have said the case has effectively been closed.
John Henry's injuries are so severe that he cannot walk, is not expected to return to school until the New Year and faces a number of operations in the years ahead to repair the damage which left him with deep cuts and lacerations to his calf where the dog sunk its teeth into his calf.
Natasha said: "It is absolutely horrific. He can't sleep, he keeps having nightmares and he's crying.
"He has been in so much pain and we don't know if he will be left with a permanent limp. He struggles to bend his leg and put his foot on the floor, he's in that much pain."
Natasha said the drama unfolded on October 6 after John Henry, who plays rugby for Bentley RLFC, was attacked by the dog at a house in Essex Avenue, Intake.
She said John was savaged after entering the house with his friend - and after hearing of the attack, his mum raced to the scene, finding her son drenched in blood and sobbing.
He was taken to Doncaster Royal Infirmary but later transferred to Sheffield Children's Hospital. Surgeons have carried out a number of skin graft operations but have warned the family that he will need many more in the years ahead as he grows and the skin stretches.
Natasha added: "The police don't seem interested. I feel like they have let me down massively. I have told them that the dog bit someone else last year, but they say there's nothing they can do and they have to give the dog back. There were witnesses who saw what happened who they haven’t even spoken to.
"I can't understand it. I'm absolutely devastated and so is John Henry. He keeps having nightmares and his mind is doing overtime.
"He keeps trying to forget what happened, but he could end up seeing that dog every day of his life. He's in so much pain and just wants to get back to walking and playing rugby.
"People are understandably concerned as the dog is walked off its lead and lives just a few feet away from a children’s park.
"The whole thing has left him very scared and he’s going to need counselling.”
A spokesman for South Yorkshire Police said: "Officers attended the scene and the dog was seized. A man was interviewed under caution in connection to the incident.
"Officers have now exhausted all possible lines of enquiry into the circumstances surrounding this incident but any new information can be passed to police by calling 101 quoting incident number 866 of 6 October.”