Oral Terbinafine is the first-line treatment of confirmed onychomycosis. Lavender oil promotes relief and treats anxiety and insomnia. The toenail. A study published in Journal of Investigative Dermatology showed that tea tree oil is effective in treating nail fungal infection. Oral antifungal medicines are the fastest and most effective way to treat toenail fungus. A neuroma may be caused by nerve irritation. Several health conditions can affect the appearance of your toenails and may be mistaken for toenail fungus.