If the nail cover is raised in the shape of an arch, it may be caused by fungal infection, trauma, or lack of micronutrients. 1. Fungal infection: due to fungal infection of the nails, commonly known as gray nails, which leads to a bulge in the nail area and is accompanied by symptoms such as thickening of the nails, turning gray, yellow and white. 2. Trauma: It may be due to the damage of subnail tissues, for example, after the finger is squeezed by the doorway, it will easily lead to hyperplastic bulge, but most of them will recover gradually by themselves. 3. Lack of micronutrients: If you are usually malnourished and lack of micronutrients in your diet, it may lead to raised nails or other symptoms, such as whitening of the nails. There are also other reasons for raised nails, so it is recommended to go to the dermatology department of the hospital in time to get a clear diagnosis and cooperate with the doctor for treatment.