If the foreskin flips out, the possible causes are: First, in patients with prepuce, the foreskin can flip out when the penis is erect, and then the tight foreskin can cause local swelling or pain in the coronal groove of the glans, and for a longer period of time, it may cause local edema to increase, which then requires timely reset treatment, otherwise it may cause local necrosis due to glans ischemia. Secondly, if patients who have had operations such as catheterization or cystoscopy can develop foreskin ectropion, after examination, the foreskin is turned to the glans coronalis, but it is not returned to its original position in time, then local edema can occur, and the ectropion is aggravated. Thirdly, when cleaning the external genitalia, sometimes the foreskin is turned out to the glans coronalis, or excessive violent stimulation during cleaning, resulting in local edema, making the foreskin unable to return to its original position, which can cause local pain or persistent aggravation of edema.