The duration of treatment for ringworm varies as per its severity and location on the body. The treatment duration is as follows:
2-4 weeks when found on the skin with topical antifungal remedies (powders, creams, lotions)
1-3 months when the scalp is affected and requires oral antifungal medication

Yes, the antifungal powder can be used when ringworm develops in moist areas such as the groin or the feet, which will help to provide dryness.

The following home remedies can be used for ringworm infection:
Use soap and water to wash the lesions of the ringworm.
Application of papaya over the affected area is effective.
Use apple cider vinegar as it has antifungal properties.
Apply tea tree oil or coconut oil to the lesion.
Apply a mixture of turmeric in little milk, wait for half an hour and then wash. Repeat 3-4 times daily.

Oral medications for ringworm include:
Terbinafine (most commonly used and should be taken for four weeks once per day)
Griseofulvin
Itraconazole

Yes, a ringworm rash is curable, though it can make you feel uncomfortable, and it can also be treated at home.