What illness is it when there is still a small amount of bleeding after stopping for a few days after menstruation?

Patient's question:

Detailed medical condition and consultation purpose: After my menstrual period, there was a few days of light bleeding. I visited the Pudong Maternal and Child Health Hospital and had a transvaginal ultrasound, but nothing was found. The doctor said I need a uterine scraping. What is this disease?
Duration and course of the current illness: Each episode lasts for three to four days, and it has been ongoing for about half a year.
Current general condition: No improvement.
Medical history: None.
Previous diagnoses, treatments, and outcomes: I had a transvaginal ultrasound and took Gynecological Qianjin Tablets and Gongxuening. After taking them for a period, the bleeding stopped, but it returned in the second month.
Additional tests:

Doctor's answer:

Problem Analysis: Disruption of sex hormone secretion leads to significant fluctuations in hormone levels during ovulation, causing obvious bleeding. Chronic endometrial inflammation or inflammatory thickening of the ovarian surface results in marked endometrial congestion during ovulation, making bleeding difficult to stop on its own. Alternatively, the rupture of an inflamed follicular surface may cause bleeding in excess of normal amounts, which then refluxes into the uterine cavity via the fallopian tubes and is expelled through the vagina. The duration of visible vaginal bleeding can range from a few hours to 3-5 days, but it rarely exceeds 7 days. In severe cases, it may persist as spotting until the next menstrual period.
Recommendations: Some bleeding may be minimal, stopping after a few drops, or may be mixed with mucus and blood. Generally, it rarely reaches menstrual flow volume. During bleeding, some may experience lower abdominal pain or discomfort on one side, ranging from mild to severe, possibly radiating to the lower back, hips, and inner thighs. Symptoms may occur monthly, every other month, several times a year, or only once in a lifetime. Recurrent ovulatory bleeding can affect fertility, and if this is the case, treatment under medical guidance is necessary.