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.
Undiluted tea tree oil has been reported to cause skin irritation in a small proportion of people. In one study, where 311 people were exposed to undiluted tea tree oil daily for 21 consecutive days, 5.5% experienced weak skin irritation reactions. However when exposed to a cream, ointment and gel containing concentrations of 25% or less of tea tree oil, no irritation occurred.