I understand how embarrassing it is for you to deal with this.
Problems with the male nipple are always serious. They cannot be taken on a lighter note.
It is not a good idea to get your trainee friend to cut it off for you.
A better option would be to meet a general surgeon
, let him examine you, find out the cause and then manage it accordingly.
Please do not leave it watch less for long time. Get it evaluated at the earliest.
Hope this helps.