The clinic is clean. The doctor had studied under-eye dark circles, so they identified my under-eye problem in one go. I was scared, so since it was my first time, I tried 2 cc of baby collagen. The swelling was very pretty swelling. But they said what was filled in now was the swelling, and after the swelling goes down, collagen would slowly fill in.
However, the pretty swelling disappeared within a week... maybe the volume was insufficient, because the collagen never really filled in. Looking at reviews, it seems people get up to three rounds, and since they said the ingredients are safe, I would be willing to try enough of it. For people who are easily scared, this seems much better than filler.