In response to the danger signal (pain, predator appearance, etc.), our body begins to rebuild its activities so as to maximize the chances of escape - either very quickly escape, or give a very strong rebuff to the enemy. In the English-language literature this reaction is summarized as "fight or flight" - "to fight or run." And this is not only a moral readiness, it is the development of various substances, spasm or redness of certain vessels, the release of hormones and immunologically active substances into the bloodstream, changes in the rhythm of breathing and palpitation, etc.
If the stress is too long, the body's strength is depleted. Then perestroika, which occurred in the body, can lead to the development of a variety of diseases - from cardiovascular to infectious.
Many of the procedures that are done to rejuvenate or beautify the skin are stressful for her. In essence, these are all procedures that damage the skin and / or cause pain. Under certain conditions, this stress plays a positive role, stimulating the skin to active recovery. But sometimes, especially if the body is weakened, the stress procedure can turn out to be the same straw that broke the camel's back. As a result, instead of skin rejuvenation, we get scars, inflammations, pigmentation disorders and even acceleration of aging.