@blaira I had a bad ankle fracture 4 years ago, and I had my titanium hardware removed. I had pain all the time like someone was kicking me in the shins, it was developing pigment on my skin over the area and I had massive chronic hives. All that resolved after the hardware was removed. It's another surgery, but not as bad as an initial injury surgery, and I could walk after ward. I was warned about fracture risk because of the holes left by the screw tracks and I had to take it easy.

I did find a few links about metal sensitivity which is described as environmental exposure.

Metal Allergy: State-of-the-Art Mechanisms, Biomarkers, Hypersensitivity to Implants
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9739320/
Titanium and Other Metal Hypersensitivity Diagnosed by MELISA® Test: Follow-Up Study
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8192180/
Metal allergy--a review on exposures, penetration, genetics, prevalence, and clinical implications
https://pubmed.ncbi.nlm.nih.gov/19831422/
I'm sorry for what you've been gong through. Getting an infection around any surgical hardware can be serious and involve a lot of further surgeries to clear an infection. I hope you get the healing your looking for.