I wondered at first if this was some kind of copper allergy, but that seems unlikely… to quote one site,
According to a 1998 report in the British Medical Journal, from 1960 to 1976, St John’s Institute of Dermatology treated only one case of copper contact allergy, which
occurred in a woman whose hobby was copper beating.
And the typical allergy reaction to copper is itching, redness and rash. I don’t have that.