Tempted as I am to simply ignore such recalcitrance, I will explain at least for the sake of others reading here.
The dermatologist says "the skin is far to elastic", eh? Well that is in part correct; that is the particular characteristic of the foreskin; it is indeed more elastic than almost any other part of the body. The term "elastic" refers to its ability, when stretched, to return accurately to its original size. Technically, the word is also used to imply that no energy is wasted between stretching and return, but that does not matter here. Part of this mechanism, is the smooth (Dartos) muscle which it contains which actively tightens it in addition to passively elastic tissue.
What is not correct, is that this elasticity in any manner prevents stretching - as Jim points out, growth occurs in tandem with the rest of the body, and this growth is largely determined by the requirement for the skin to accommodate to the body size. Specifically, fat people have more skin area than thin people, and it is not because the fat tissue sends growth hormones to the skin, but that the fat physically stretches the skin. When we refer to "stretching", we are actually not talking about a passive process whereby any material stretches when strained beyond its elastic limit, but the process of growth which is provoked by consistent strain (engineering term) on the skin.
It's nice to know that your girlfriend accompanied you to the dermatologist. I'd like to know whether she has also accompanied you whilst you browse here?
Your girlfriend is a "nymph"? Not sure what you mean. You perhaps mean "nympho", colloquial slang for "nymphomaniac"?
What really worries me is that your original posting was a month ago, but you consistently fail to mention what stretching you have been doing in that month, how often during the day and for how long each time, and consequently, what you have achieved in terms of retraction in that time?