I am sorry to break it to you but when you work in a profession FACING the client, you need to present yourself in a discreet manner. That means tightly worn hair and no visible tattoos nor piercings.
Moreover, why would you wear a visible piercing at work? Your personal life should not interfere with your professional job. If I had someone going down my mouth with a pierced nose I would subconsciously question their validity and possibly ask the doctor to have someone else do my dental work. Not only do I think like this but so would many others. If you weren't born with it, I don't want to see it as a customer that I am.
And for the record, I have long hair (check my sig) so it is not like I am against freedom of expression but you have to think of what others, who are going to pay YOU, will think.