I have used this product twice. The first time I used this product, I was not able to stamp my face for the length of time it takes to use all of the serum. I probably used 1/4 of the serum by stamping and dabbed the rest on my face. The second time, I was able to stamp my face using 1/2 of the serum in the vial and dabbed the rest on my face. I have to admit, I did notice a positive difference even though I wasn't able to stamp all of the serum on my face. My skin is looking more vibrant, smoot...