https://blogs.mercola.com:443/sites/vitalvotes/archive/2019/10/02/toothache-medication-causes-blue-skin-nails-and-blood.aspxA numbing agent for toothaches was to blame for the blue skin, nails and even the navy blue blood of a 25-year-old woman who was diagnosed with methemoglobinemia — a rare blood disorder — at a Rhode Island hospital, according to The GuardianenCommunityServer 2008.5 SP1 (Debug Build: 31106.3070)