What Causes Rashes And Pus Formation On The Penis?

sir i am 30 yrs old.i have rashes and pus formation on my pennis for the past 1 month.i consulted doctor and he prescribed Bludrox,dolo650,triz.At the time of intaking this the problem was subsided and again it recurs.Then i consulted another doctor he prescribed cepodem & rantac tablets,i continued with this morethan a week,but still i have the problem.Please help me out