Benzocaine numbs mouth pain in 60 seconds — but the FDA has received 322 methemoglobinemia cases including 7 deaths. This 2026 guide covers safe use, the 7-day OTC limit, why it must NEVER be used in children under 2, the grey-skin emergency warning, an 8-treatment comparison table, caine allergy alert, and the 3-week ulcer rule that could save your life.