Rhinoplasty to reshape the nostrils
A rhinoplasty procedure can accomplish narrowing the bulbous tip, shaving down the dorsal home, decreasing the projection of the nose, and narrowing the bridge. AN alar-plasty is performed to narrow wide nostrils, Not decreased the length of them. For more information and many examples of rhinoplasty, please see the link and the video below
Rhinoplasty: reshaping the nostrils
Rhinoplasty is a surgery to change the shape of the nose for breathing or appearance.The nostrils bring air into your nose. They may be uneven at birth. They may become uneven over time. There are rhinoplasty technique to improve the symmetry of the nostrils; however it's more important to consider the whole nose as it relates to the rest of the face. Your face is viewed from the front most of the time, followed by the angle and side views. The base view, where the nostrils are most visible, is seen the least. I would recommend meeting with a rhinoplasty specialists who can examine you, explain the features of your particular nose before discussing treatment options appropriate for you. This includes doing nothing. Safety comes first.
It is hard to comment without seeing your photos but based on your description it appears that you would be a good candidate for rhinoplasty, such as the example in the link below