@anamur-- You know there are also home kits for collagen facials that are much more affordable. I saw it online a while ago. It was half the cost of a collagen facial at my doctor's office.
The only concern I might have about these kits is the absorption issue. The article did a great job pointing that out. My doctor had also told me this at one point, that collagen molecules are too large for them to be absorbed by our skin. That's why when professional beauticians do this facial, they use special ingredients in the collagen face masks and heating techniques to help the skin absorb.
So there is a risk that you might buy the home kit and get no benefits from it. It might be best to go to a professional who has experience. I think that the nicer (and more expensive) collagen facial you get, the better the results will be.
I went to one of the best places for mine and they even provided several collagen serums and creams to continue using afterward. The results lasted a pretty long time for me, I would say about six months or so.