How To Ensure Toenail Adherence To Nail Bed And Prevent Bacterial Infection?

I had a toenail fungal infection several, several years ago. I cut the fungus away myself because I did not have health insurance or money to go to the doctor. In the past two years that has changed so I have been under dermatologist's care for this issue. I no longer have a nail fungus, however, the toenail will not adhere to the nail bed where I had cut the nail away. Last year, because of this, I got a bacteria under my toe when I went on vacation and was in the water a lot. How can I get the nail to adhere to the nail bed OR how can I keep bacteria from growing here when I go on vacation/swim?