Uneven nail cover can be caused by gray nail, trauma, bacterial infection, lack of nutrition and other factors. 1. Gray nails: After gray nails occur, the accumulation of dander and keratin under the nail plate is easy to occur, which can lead to uneven nails and discoloration. 2. Trauma: after a history of hand trauma and nail bed injury, the nail bed may not heal smoothly, resulting in unevenness of the newly grown nail plate. 3. Bacterial infection: due to poor local hygiene and cleanliness, or due to long-term nail polish or nail art, it is easy to lead to bacterial infection of the nail, which may lead to unevenness. 4. Lack of nutrition: when the body lacks certain vitamins and trace elements, which affects the nutritional supply of nail matrix and leads to its abnormal function, the synthetic nail plate may appear bumpy. There are many other reasons for the unevenness of the nail cover (such as psoriasis causing thimble-like changes in the nails), under the guidance of a doctor to clarify the cause of the disease and then carry out the appropriate treatment, which will help to alleviate the uncomfortable symptoms as soon as possible.