duzzpi review for Pigmentbio C-Concentrate

I have been using this serum for 3 months. Firstly I have to say,I haven’t used it everyday as it is suggested. My skin became sensitive when I used it, so as of now I’m unable to see if the serum works on dark spots or not. Although it makes my skin smooth. I have seen how it affects my whiteheads and how it makes my skin brighter. I combined it with TO Niaciname serum and my skin has been the brightest I’ve ever seen. Also it has worked on my whitehead below my under eye area where the cosrx AHA tonic didnt work before. It's more like an AHA serum than a C vit serum. I opened 3 months ago and am yet to finish it. It has no oxidation.