[Routine Help] what happens at an aestheticians visit?

I accidentally stumbled across a bunch of aesthetician yelp reviews that made it sound like they are hugely improving peoples skin, and I'm wondering by what methods? I assume a lot of it overlaps with the SCA routine but it sounds like skin lighteners, peels and masks are also involved, along with likely a bunch more.

I've never been to an aesthetician before, what happens during a visit? What kind of advice and products do they give you? I'm very curious now!