Small bumps under the eyes may be caused by cornu rashes, sweat duct tumors, flat warts and other causes. 1. Corns: These are benign swellings or retention cysts originating from the epidermis or the epithelium of the appendages, and are found in the facial area, especially around the eyes. It manifests as yellowish-white hard round papules on the surface of the skin, which may lead to the growth of small bumps under the eyes. 2. Sweat duct tumor: it is a benign tumor belonging to the duct of sweat glands, which is common in the face, especially in the lower eyelid. It is a yellowish or yellowish-brown semicircular flat papule, which can also lead to small bumps under the eyes. 3. flat warts: human papilloma virus infection caused by the skin benign redundancy, the formation of rice grains to soybean-sized flat pimples, smooth surface, hard texture, normal skin color or light brown, may also appear under the eye long small bumps. There may be other reasons for the bumps under the eyes, so it is recommended to go to the hospital for examination and treatment as prescribed by the doctor.