I had my belly button pierced when I was younger and then had it repierced about 4 years ago.
I don’t know if the scar tissue caused a problem or what, but it took about a year to heal. I did the Betadine thing, then peroxide, Neosporin, with hazel and even rubbing alcohol.
The only thing that got rid of the infection and helped it to heal was a solution of salt and water applied twice a day. Mix it as you would if you were going to gargle with it.
It started to work very quickly and within a month of using it the hole had healed.