Skin Rejuvenation + Vitamin C Q&A

I have both, and just wonder if the order you apply them, or using them a.m. and p.m., has a greater effect..

I started hyaluronic acid in the A.M., which also has vitamin C. After reading about C, I wonder if a C serum would be helpful as well, but am not sure how to use it.

Is is necessary to use a Vitamin C serum even if your sunscreen contains Vitamin C and other antioxidants packed into its formulation? Won't the vitamin C already in these products do the work of a vitamin C serum? Dermatologists seems to want to sell a Vitamin C serum to everyone.

What is a proven method/treatment to get rid of the acne scars (divots/holes) & uneven skin texture, and perhaps target collagen/elasticity loss & fine lines. I'm 29 yrs old. Glycolic night repair, vitamin C oil, glycolic face mask, etc. NIR Red Light therapy I had hydra facials, and AHA/BHA skin peel and nothing helped with the scars/holes or smooth texture. What will help me achieve smooth skin for sure & how many treatments? Thank you!

Am currently using Skinceuticals blemish + Age defence wash, Skinceuticals blemish +Age Defense,Skinceuticals hydrating B5 gel, Skinceuticals Retinol 0.5 and skinceuiticals physical fusion UV Defense. I recently purchased the Clinique fresh pressed daily booster vitamin C and am confused as to how to incorporate it into my routine?

Oily skin type, not fair skin