An ingrown toenail occurs when the edges or corners of the toenail grow into the skin, causing pain and irritation. It is commonly caused by improperly or tightly cut toenails, ill-fitting shoes, injury, or fungal infections. Early symptoms include redness, swelling, and pain at the edges of the toenail. At-home treatment involves soaking the foot, keeping it dry, gently massaging, placing cotton under the nail, and using topical antibiotics. Prevention involves wearing comfortable, loose shoes and trimming toenails straight across at the edge of the toe.