Angel Ruiza, owner of Anarchy Tattoos and Art Co. in Orlando, contacted King and offered to do the job free of charge.
"I was excited and amazed at how fast it all happened," King said.
Ruiza, who also did free Pulse-themed tattoos after the June 12 nightclub shooting, asked King what her son liked and they settled on a shark theme.
Now, instead of a conspicuous white brace, Xavier is sporting a nighttime ocean scene with a great white shark and detailed moon and sky.
"He was shocked and instantly wanted to wear it to school to show all his friends," King said.
She couldn't thank Ruiza enough for what he did for her son.
"I cried," she said. "I never expected it to be so amazing and full of details ... I'm so grateful that something like this has changed my son's confidence and makes him smile."