Suggest Treatment For A Marble In The Urethra

Hello i would like to know what is this thing by my urethra. It feels like a little marble in the inside but on the outside it shows like if a pimple was starting. It has been like this for a week and when it happened my penus was bruised up. It didn t really hurt much but am still wondering if its anything serious? This was cause by dancing grinding . I couldn t tell until i was done and went to the bathroom and saw my penus purple/blackish with that lump. The purpleness is almost gone but the lump seems to not change. Hoping i could get help on this if it will get better naturally without having to go to a doctor.