What can i do to fix a bad toe nail?

Toe nail: Depends what caused the condition. If fungal it would need to treated with an anti-fungal medication or with some type of debridement. The nail may have injured in the past and need surgical correction. An ingrown nail may cause a local infection and should be removed by podiatrist.

What is causing it: Depends on what you mean by "bad" toenail. See a podiatrist and after diagnosis, a correct treatment will be provided to fix your bad toenail.

Depends on the cause: Some causes of abnormal nail growth include trauma, infection, side effects of medication, and possible systemic diseases such as psoriasis. Have them inspected by a professional to determine the cause of the problem, as treatment varies depending on the diagnosis.