The redness and swelling of the foreskin of the penis hurts when you touch it, which may be caused by acute injury, infectious factors and allergic factors. 1. Acute injury: the penile foreskin area has been excessively squeezed or foreign body stimulation, resulting in localized damage, which will cause local redness and swelling and other symptoms, and it hurts when touched. 2. Infectious factors: male presence of phimosis and phimosis, do not pay attention to the lower body hygiene, may be induced by glans phimosis, due to inflammatory substances stimulation, will lead to redness and swelling of the foreskin, pain, may also be accompanied by itching, and in severe cases, may be broken and pus. 3. Allergic factors: such as the existence of allergic reaction to toiletries, when the allergic reaction is serious, it will lead to the foreskin red, swollen and painful, accompanied by intense itching, and the local will appear red pimples. The penile foreskin is red and swollen and a little painful when touched, it is recommended that men seek medical treatment for appropriate examination and treatment, to avoid aggravation of the lesion.