It usually starts in the nerves farthest from the brain and spinal cord -- like those in the feet and hands. Then it may move up into the legs and arms. However, if you get treatment for the medical condition causing the nerve damage, you may be able to stop the damage -- and even reverse it.
If swallowed, tea tree oil can cause varying side effects ranging from drowsiness, upset stomach, vomiting, nausea and weakness, to coma, hallucinations, blood cell abnormalities, confusion and ataxia which affects muscle coordination and your ability to move voluntary muscles, states the American Cancer Society.
A 2006 review of the toxicity of tea tree oil concluded that it may be used externally in its diluted form by the majority of individuals without adverse effect (provided oxidation is avoided). Topical application of tea tree oil can cause adverse reactions at high concentration. Adverse effects including skin irritation, allergic contact dermatitis, systemic contact dermatitis, linear immunoglobulin A disease, erythema multiforme like reactions, and systemic hypersensitivity reactions.