If you actually look at the ingredients/formulation of Korean or Japanese skincare products, most of them are not unique at all.
Koreans who eat a more traditional coastal Asian diet have better skin because of the low glycemic load of mostly rice, veggies, and fish. High glycemic diets (the typical American diet) are notorious for aging skin (high glycemic loads contribute to loss of collagen) and contributing to acne.
Many Koreans also have great skin because they avoid the sun like the plague, while a lot of Americans and Europeans worship the sun. Next time you go to Korea or Japan watch how many girls are out there walking around with umbrellas and "facekinis".
I have a great Korean friend who had perfect, porcelain skin for most of her life. She moved to California in her twenties. Within a year of changing her diet...and it wasn't even that extreme, just adding regular milk consumption and the occasional fast food item...she had moderate acne. She still only uses "Korean" skincare products...didn't help one bit.
I can't remember if I already said this, but for some people retinoids just don't work. They will turn small sebum plugs into cysts. Retinoids have always done this for me. I just can't touch the stuff.
Even after I cleared up on spiro (meaning ZERO zits), my skin isn't perfect. I get little blackheads here and there. I tried adding back in retinoids after I'd been clear for months and got a whole crop of deep bumps. It was really frustrating.
Tazorac is also one of the strongest retinoids out there. I would just stop using it.