There are many clinical conditions that can cause painful swelling at the root of the thigh. Patients with painful swelling that appears on the surface of the skin and is imagined to be red, swollen, hot, and painful can be diagnosed as a sebaceous cyst. This is a very common clinical condition in which the patient will experience pain at the root of the thigh and will have hard nodules that are hard to the touch at the root of the thigh. In addition, enlargement of lymph nodes is not excluded. In addition to the above diseases, patients with lumbar disc herniation compressing nerves may also experience pain in the thighs, but this pain is rarely associated with localized redness and swelling, which is easier to distinguish. If the symptoms are more frequent, it is recommended that patients go to the hospital for further consultation to avoid delaying the condition.