Megan Fortune, four, needed 12 stitches after a Rottweiler mauled her face while she was at her grandmother's home in Suffolk.
The owner of the dog has escaped prosecution because the attack happened on private land. Owners can only be prosecuted if a dog attack occurs on public land, not private property.
Mary Hockley, Megan's grandmother, was looking after the dog - which is reportedly a Rottweiler German-Shepherd cross - for a friend at her home in Felixstowe when the attack happened.
When Megan's mum, Elizabeth, 25, reported the attack, she was told because the dog was in a private place, it meant no offence had taken place under the Dangerous Dog Act.
"'I just find it hard to believe that a dog can do that, let alone to a child, and there are no repercussions," says Elizabeth.
"I think it's ridiculous. I would absolutely love a change in the law. Even if it said the dog would need to be muzzled near children, I believe there needs to be something changed because I find it amazing a dog can do that and nothing can be done about it.
"He has always been a lovely dog. We have had a lot of contact with him over the past four years. He has never shown any sign of aggression which is why it came as such a shock - we were just completely gobsmacked."
Megan needed stitches above and below her eye, and on her jaw line. Although she is making good progress, she is said to me making a good recovery, but is said to still be very traumatised after the attack.
The dog's owner refused to comment to reporters.