Stone has stucked outer side of penis.

Sir since  5-6 days , urine started pass slowly slowly through penis with pain, yesterday suddenly during urinet it mostly jamed & high pain, it comes drop by drop with huge pain, Then it took alkasol syrup , after some hours there is little bit relax I feel , but not much ,I feel that something has been stuck inside part of penis, But today's morning something is appearing outside part of penis with black colour, what is it ? I don't know , but I guess it is stone , and urine has been blocked mostly, and a lot pain during urinet, urine comes in form of drops, Whole day completed but stone has been stuck outer side of penis, it is appearing black colour from outside, it is not coming out, Please tell me sir what should I do??? Please suggest me in a best way soon???