I Have a Very Narrow Face. Would Sculptra Make It Rounder Than when I Was Young? I Would Rather Not Change the Shape of my Face

I would encourage you to see a board certified facial plastic surgeon for an evaluation to see how much Sculptra should be used.  

Sculptra injections are very technique dependent, and require experience and artistic three-dimensional analysis of the desired volume changes of the face. As long as you are clear with your doctor about the results you want to achieve, the shape of your face should not change.

The goal for most people is not to change their anatomical shape, but to restore volume that has been lost to regain a more 3-D effect associated with youth and energy - or to balance the proportions of one side of the face with the other when there is obvious asymmetry.

Sculptra works differently on different people.

Sculptra generates collagen more quickly and more profoundly with younger patients, so less is used. More mature patients with pronounced volume loss and less efficient collagen-building response take more product and more sessions. As the procedures are undergone over several sessions, there is considerable control as to how much volume replenishment actually occurs.

Sculptra treatment is generally multi-area focused

A great deal of the result is technique driven and seldom is a single-area approach applicable to mature patients. Generally if you've lost volume in the face, then you've also lost volume in the temple area, in the lips,  the chin or jaw area and in the brow area. Best results are achieved with a whole face plan so all the areas synch up and belong with one another.