There is a hard lump inside the foreskin, consider with folliculitis, sebaceous cysts, warts and other diseases, you can go to the hospital for further examination to clarify the cause of the disease, and timely treatment of the cause. 1. Folliculitis: it is caused by excessive secretion of oil from hair follicles and blockage of hair follicles, etc. Folliculitis will cause pimples to appear around the skin, and then there is a hard lump inside the foreskin. 2. Sebaceous cysts: usually due to the sebaceous gland excretory tube blockage, sebaceous cyst epithelium is gradually increasing the content of the blockage, expansion of the formation of retention cysts, and sebaceous gland obstruction, so that sebaceous secretion of accumulation, and then appear inside the foreskin there is a hard pimple of the phenomenon. 3. Condyloma acuminatum: generally due to unclean sex, HPV virus infection and long-term smoking and other factors, the skin around the penis in the HPV virus stimulation, caused by the phenomenon of a hard pimple inside the foreskin. If there is a hard lump inside the foreskin, it may also be related to genital herpes and other diseases, you need to go to the hospital in time to avoid delaying the condition.