Well written post and great photo's,
That's one serious bacterial infection you've got there!. I imagine it came from either a coral scrape or chafing from sand in your flats boots or socks.
Here's a word of advice from someone who's gone through the same...On your next fishing trip to tropical waters, bring a fully complete first-aid kit that includes iodine and anti-bacterial cream. The most important addition to that kit would be a generous roll of waterproof duct tape. Clean, treat and dress the wound as per normal (iodine/cream/gauze pads),...then overwrap the works with the duct tape to keep your dressings dry and clean.
Believe me! I know what you went through and I'm sure you've been left with some ugly scarring that will never go away...mine didn't! It's amazing how the most minor of irritations turn into ugly septic infections after being exposed to all the various bacterias found when wading flats.
Once again...looks like you had a great time!