Mr Campbell had shaved his head completely to get the tattoo done but said he would be letting his hair grow back.
He'd shave it off again and show off the tattoo at "special occasions," or if Charlotte wanted to see it.
When Charlotte saw her dad's version of a cochlear implant she giggled, touched it and told him it was "cool".
Charlotte's mum, Anita Campbell, wasn't so sure her daughter had quite grasped the significance of the tattoo yet.
She hoped her daughter's latest implant in her right ear would further "enhance her life".
Mrs Campbell's mother had a cochlear implant and her second-son, Lewis, 8, wore hearing aids so she wasn't surprised when Charlotte was diagnosed.
She said things were a bit "up and down" for a while as the diagnosis evolved from just a mild hearing impairment, to the news Charlotte was profoundly deaf in her left ear and had a condition which limited the ability to transmit sound to her brain in her right.
Mrs Campbell said Charlotte's first implant in her left ear saw an immense change in her daughter's behaviour.
"She wouldn't talk to anybody to pretty much a social butterfly," she said.
The Hearing House fundraising and communications manager, Mary Jane Boland, said this second implant would give Charlotte "more sound" and help her better distinguish the direction it's coming from.
"But the key thing is Charlotte does all the things hearing kids can do," she said. "She lives a really ordinairy life."
A photo on Twitter showing Mr Campbell, holding his daughter, with the picture of the implant tattooed on his otherwise bald head, has gone viral on social media.
People from as far afield as France and Germany praising Mr Campbell for the tattoo.
Filip Dakic tweeted, "Wow. Respect! Getting through it together with his daughter."
Anatol tweeted, "Quelle beau geste [ what a beautiful gesture] Getting through it together with his daughter."
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