"
Fear is under my skin
Like St. Anthony's fire
And I can't stand the burn
St. Anthony's fire can describe any of three different diseases, but in this case most likely describes erysipelas, an acute infection that causes a bright red skin rash. It was named for the saint to whom Catholics in the middle ages would appeal for help with the ailment. In this case it seems that healing has either not taken place, or has not been ordained.