I'm thinking of getting lip fillers for the first time. Will it swell a lot?

My lips are naturally on the thinner side, so I'm considering lip fillers because I think even a little bit of volume would change my impression.
I don't intend to make it too thick; I just want it to look pretty and natural. Since it's my first time, I'm not sure how much is appropriate to put in.
I've seen many reviews saying that the lips swell a lot after the procedure, so I'm wondering how many days it usually takes for them to look natural.
For those of you who have actually received lip fillers for the first time, please share your experiences regarding what was different from what you expected or what you were satisfied with.