Use old rags, because lye weakens cloth fiber. You'll notice itching before burning. Rinse your hands with vinegar and immediately rinse them with running water. Lye can be fatal if swallowed. Take them to an emergency room immediately.
Fumes also come from the stirring container.
With prolonged contact, fumes can burn the eyes and skin of sensitive people. Thousands of people make soap without mishap. In order to do so, you must be aware of all safety hazards. Children, pets and feeble-minded people should not be in the soapmaking area or have access to stored soapmaking ingredients, especially lye and essential oil. Be sure the thermometer doesn't touch the bottom of the container and give a false reading.