I would like to inquire about lip fillers to add volume to my thin lips!

I am considering lip filler treatment and would like to receive a consultation. I am writing to inquire.
I want lips that have natural volume and a clear lip line, rather than lips that are excessively thick.
Since this is my first time getting fillers, I am not sure which product and dosage are suitable, so I would like to receive a professional consultation.
In my case, I am wondering if it is better to have the procedure done on both the upper and lower lips, or if I can achieve natural results by focusing only on the upper lip.
My lips are naturally on the thinner side, so my face looks a bit flat. In particular, my upper lip lacks volume, so I really want to fill it out.
I am asking because I saw reviews saying it doesn't fit well since the upper lip can sag and the philtrum can lengthen.
I would also like to know if I can expect better results by combining procedures to correct the corners of the mouth or refine the lip line.
Please provide information on the type of filler used during the procedure, the duration of the effect, and whether there are individual differences.
Also, I'm curious about how much pain there will be during the procedure and how the anesthesia is administered!
I would also like to know if it is okay to apply makeup immediately after the procedure.
I would appreciate it if you could also let me know if there are any special precautions after the procedure, and if a touch-up is necessary, when would be the best time to get it.