Isn't Sculptra a procedure that makes your face plump?

My face became so thin while dieting
Looking at old photos, it seems like my face actually had more volume than it does now.

While fillers provide immediate volume, there is the burden of having to properly shape them.
I'm looking into Sculptra because I heard it's a method where you see gradual changes.

However, looking at the name alone, it is easy to think that it involves injecting fat.
In reality, it is different from a procedure that creates the desired volume immediately, right?