first of all, the piercing is not meant to be in your body, so naturally your body is going to decide whether its easier to accept of reject the jewelry. if you find a good place to do it and the person is qualified you shouldnt have a problem with this because they way the piercing sits you cant even feel it.

if you look after it the worst that can happen is it rejects and thats not a huge loss because you can either get it again or accept it

i love my nape piercing, i wanted it for 3 years before i got it done because everybody thought it was gross, or stupid. finally i decided to go with it because 3 years on i still wanted it, and people still thought it was gross and stupid!

if you want it, just go for it!