What Causes Pimples On The Foreskin?

Hi, i m 19 year old n my weigth is 58 kg i m muastring since 14 yr n now from two year i m muastring twice or sm time 4 times in a day my penis pain smtime n my body is also started pain n some white pimple types spot arise under my above skim of penis what is that white pimple n why my body pain so much