thanks for using health care magic.
It is hard to say what actually is the cause since your description is
a little not detail as to whether its inside the scrotum
or not, painful
or not, affecting urination or not etc.
If its on the scrotum it could be a condyloma or tumor
or in rare
cases a kelloid.
However, if its inside the scrotum it could be one of a diverse range
of causes as well including tumors, varicocele
, bubinocele etc.
So the best thing to do will be to go on with the appointment and let
the doctor examine.
Best regards and hope he gets well soon.