If I don't like the shape after the filler, can I get it corrected immediately?

I'm wondering if fillers produce the exact shape you want right from the start.

After the swelling goes down, it is a little less than I expected or
Conversely, I also want to know what to do if it looks too voluminous.

Is there a case where it is added immediately?
Or I'm curious if they might wait a while and then make a decision again.

Those who have actually received it, when you have your first consultation
I'm also curious how you described the shape you wanted.