The subject of "Skin Rejuvenation Treatments" is so broad that one answer can not adequately encapsulate it. The response to "What's the best skin rejuvenation treatment?" will have to wait until the end of my piece.
Simply put, a skin rejuvenation treatment is any measure undertaken to restore the skin to its original, youthful appearance. Usually this means eliminating wrinkles, folds, hollows, laxity, rough spots and growths, "broken" blood vessels, and irregular or blotchy pigmentation. In its broadest sense, skin rejuvenation would include any "what you can do for yourself" measures, including dietary or lifetstyle changes, or home care routines that may impact favorably on the skin. This would include avoiding smoking, excessive alcohol, tanning parlors, and too much natural sun exposure. It can mean exercising regularly, drinking adequate fluids, eating nutritiously, taking the appropriate vitamins and supplements, adopting proper cleansing routines, and using sunscreens and moisturizers regularly.
It might likewise entail a whole list of the routine use of over the counter (OTC) products that contain retinol, alpha hydroxyacids, antioxidants, peptides, growth factors, and pigmentation lighteners. It would certainly encompass a long line of "what your doctor can do for you" remedies, including the use of by-prescription-only products containing retinoids (like Retin A), and high potency alpha hydroxyacid compounded topical products.
Other in-office, non-surgical techniques for skin rejuvenation can range from radiowave therapy for treating "broken blood" vessels (more correctly known as "telangiectasias" or dilated tiny vessels) and removing brown spots; Radiowave skin tightening and microneedling for softening skin crinkling and crepeyness; superfical "lunchtime" peels (like glycolic acid "fruit wash" peels) and microdermabrasion, for brightening skin and giving it luster; Botox & Dysport injections, for eliminating and softening the lines of facial expression; fillers for fine lines and wrinkles: volumizers, for deep folds, jowls, hollows, straightening bent noses or falling tips, and for recontouring lost cheeks and chins; the Ten Minute Eyelift, to improve upper lid hooding; and the Ten Minute Necklift, for helping diminish "turkey necks".
From this broad overview, which did not even touch upon aggressive, invasive surgical procedures like facelifts, necklifts and eyelifts, it should be clear that the subject of skin rejuvenation is vast and too much for one question and one answer. So, with so many things to choose from, it should be clear now that the response to "What is the best skin rejuvenation treatment?" really depends upon who is asking. Today, a cosmetic dermasurgeon can tailor make a regimen of at-home maintenance therapy and in-office treatments according to the specific needs of the individual and his/her budget. Depending upon the circumstances, what will actually prove best may be one treatment or a combination of methods.
For more information, I suggest you research the subjects noted above. However, to really nail down what is best for you, I also advise a consultation with a physician who specializes in esthetic skin care.