How do dermal fillers work?

Ask how one named filler works, not how fillers work as a group.

Name the product first

The answer belongs to one specific product. Get the product name from the injector, then read that product's labeling.

Ask the injector about one product, in order

"Filler" is a category, not a single product. Ask the injector these, one after another:

1. What is the product's name?
2. Where on my face will it go?
3. What does the labeling say the product is for?
4. What does the aftercare sheet tell me to do and to avoid?

Open the FDA list of approved dermal fillers and look for the product name the injector gives you. Then read the FDA consumer update on dermal filler do's and don'ts next to your aftercare sheet, and note any gap in the sheet.

Write the product name down and read its label at home

1. Write down the product name before the consultation ends.
2. Read that product's labeling at home, not in the treatment chair.
3. Ask what you should report after the visit, and to whom.
4. Decide only once every answer is on paper.

Ask where the injector's explanation comes from

A confident explanation is not a documented one. Ask the injector which document backs what they told you, and have them walk you through the product itself.