The penis grows a small red bud, pus may be related to folliculitis, genital herpes, warts and so on. 1. Folliculitis: purulent inflammation occurs due to bacterial infection, initially red congested papules or pustules, the rapid development of the back of the hearing evolved into papular pustules, pustules in the middle of the pustules through the hair, surrounded by a reddish halo. 2. Genital herpes: a sexually transmitted disease caused by herpes simplex virus infection, occurring in the penis, glans, scrotum and other parts of the body. The skin lesions are characterized by clustered pinpoint-sized herpes, which breaks down to form vesicles. 3. Condyloma acuminatum: a skin and mucous membrane disease caused by infection with the human papilloma virus. In the penile area, there are single or multiple papillae, papules and other moist fleshy organisms. The surface of the papules is prone to erosion and bleeds easily when touched. The penis grows a small red bud, pus may also be caused by other factors, it is recommended that patients go to the regular hospital in a timely manner, follow the doctor’s instructions for further examination, in the doctor’s help for targeted treatment, and strive for early recovery.