What you are describing is poison resistance where consuming a toxic substance makes your body more tolerant to its adverse effects. It makes total sense for n

What you are describing is poison resistance where consuming a toxic substance makes your body more tolerant to its adverse effects. It makes total sense for nut allergy where the disease is the intolerance; if you become immune to the substance you are cured. Toothache is not an intolerance to deadly nightshades and no level of resistance to the poison will cure what is a totally unrelated issue; pain caused by a something slowly digging a hole through my gum.