The symptoms of a pierced nose infection aren’t very different from any other piercing infection. The area around the hole will often become inflamed, the skin may redden, and the infected flesh might become hotter than the rest of the body. If it’s severe enough, the wound will generally produce a discharge of pus. Sometimes the infection can progress, causing the person to develop a fever. For some people there is also swelling with an infected piercing, and they may even develop a lump called an abscess near the spot where they were pierced.
Piercings can make it easy for bacteria to get into a person’s blood stream, and when this happens, it makes it hard for wounds to heal properly. Sometimes the body can fight off bacteria pretty easily, but not always, especially if the bacteria are established inside an open wound. When people pierce themselves, the general idea is to keep the wound open long enough so it heals around the piece of jewelry, leaving a perfect hole. This makes it harder for the body to fight off bacteria, and it makes infection more likely than it would be with a normal injury of similar size.
There is also the question of hygiene around the piercing. Sometimes a pierced nose infection can happen much more easily if a person doesn’t take special care to keep his or her nose ring very clean. When the nose ring is removed, it can easily be contaminated by bacteria, making an infection more likely. For this reason, professional piercers and doctors usually expend lot of effort educating their patients about piercing hygiene.
If infection symptoms get to the point to which a fever has developed, it could be considered an emergency situation. With any infected wound, there is always a chance of blood poisoning, which is very serious and could even be fatal if left untreated. In most cases, people are able to deal with a pierced nose infection on their own. Usually people simply continue using antiseptic and cleaning around the wound until the infection clears up.
After a piercing, the nose can take a little longer to heal than some other piercings, partly because the hole goes through cartilage. This could potentially make the wound more likely to get infected because the it will be open longer. In terms of seriousness, nose piercing infections aren't generally considered any more dangerous than other piercing infections.