Chloe, 19, who does not want to give her last name, suffered 24 burns in the blast, and was told she would be scarred for life. But incredibly Charlie's charred teddy bear snowsuit had saved him from horrific burns, which could have killed him.
Chloe and Charlie had been walking home from her mother's house with her boyfriend Brandon, 19, and their dog at around 11.30pm on Saturday when the firework was thrown at them as they passed a pub called The Bosun. The firework flew underneath Charlie's pram and exploded against the wall next to him.
'We saw some people playing around with fireworks outside the Bosun pub,' Chloe said.
'We didn't know what was happening at first.
'We saw the men light a firework, but thought it was a Catherine wheel that they had left on the floor.
'Then all of a sudden it came shooting towards us.
'We didn't have time to move out the way - it just happened so fast.'
Chloe says her dog anticipated the attack and dragged her partner away before the firework hit him. Charlie was asleep in his pram when the firework exploded and he woke up screaming in fear.
Chloe said: "My legs were burning and I ran into the road in tears, screaming. I was petrified because at that point I didn't know what had happened to my son. He was really scared because it banged right next to his pram. He screamed all the way to the hospital and I just couldn't calm him down..'
Chloe has been left with burns on her face and chest. She has been told three of the injuries will leave her scarred for life.
But although the flames from the firework burned Charlie's snowsuit, he was unhurt.
Chloe said: 'My son was burnt, so the paramedics took his suit off to make sure it hadn't gone through.
'They were obviously very shocked because the suit had saved him.
'Doctors said it practically saved his life.'
Charlie had been given the snowsuit as a present from an aunt when he was born, but had only just started to wear the suit as the weather got colder.
She said: 'I was going to put Charlie in some jeans and a T-shirt, but my partner said to put him in the snowsuit instead.
'I'm glad we changed his outfit because it could have been a lot worse.
'We'll definitely be investing in another suit.'
After the attack, Brandon went across the road to confront the men. However, they threatened him and told him they would burn the family's house down.
Both Chloe and Brandon had been left temporarily deaf in one ear because of the noise of the explosion.
Brandon also suffered minor burns.
A spokeswoman for Humberside Police said: 'Police are investigating reports of malicious wounding as two people were injured when a firework ignited next to them as they walked along Hessle Road in Hull.
'The man and woman sustained burns as a result of the incident.
'The couple's baby, who was being pushed in a push chair at the time of the incident, was not harmed.'
Police described one suspect seen outside the Bosun pub as being tall, bald, aged about 30 and wearing a dark jacket.
The other was described as about 60 years old, tall and of skinny build with grey hair.
