Nobody is entirely symmetrical, but sometimes the inside of your nose is less symmetrical than the outside and thus a septum piercing can some out less than perfectly in the centre. With a little more precision and attention to detail, a good septum piercing can still be established.
As opposed to what many people think, a septum piercing is also possible on a slightly crooked nose. It just requires more precision and skill. If done well, the piercing can be put in such a way that the nose is not only decorated but also appears straight.
Below: a handful of pictures of septum piercings, I’ve performed. If you have any questions send me an e-mail at firstname.lastname@example.org.