Reason For Pimples On The Foreskin Getting Strong In Size

Hi im 26 and have a pimple on the foreskin of my penis, i have not had sex with girls. Weekly 3 or 4 times I do the hand pump. I have well sex feelings. The pimples getting spared round to my penis at slop circle, and pimples getting strong in size, when I am moving my penis skin then they getting touch to my hand, I get the rub my penis then I get the painat pimple place. I got the pimples at slop circle in penis. Please tell how to solve the problem through medicines, please help me, I am getting marriage next month. Please try to help me, Please help.