The most common fugal infections are a form of tinea, or ringworm...yep, they are known collectively as “dermatophytes” aka "nail fungus".
Go to the drug store and get some sulfur and an eye dropper if you don't have one, mix a very runny solution of sulfur and water, use the eye dropper to squeeze as much of that sulfur solution under the nail as you can and all over the toe.
Lift the nail up as much as you can bare, or pull the skin downward while doing this.
Also start taking an MSM supplement. There is no contraindication for MSM, it is a natural sulfur found in fruits and plants.
Heres why kitty...
If you maintain a good sulfur level in your body, you will never have worms of any type. Thats why I suggest the MSM, which helps promote healthy skin and fight eczema too.
The yellow type sulfur I suggest you buy from the drug store is for external use only, you make that into a very watery solution.
If they only have flowers of sulfur at the drug store...then settle for that.
Tea tree oil or oregano oil is 80% effective for it, that leaves 20% of the people it will not cure.