Please recommend an ampoule or serum that is effective even with just a small amount!!

I'm really worried because my skin has become so dry lately, probably because it's winter. Usually, I didn't have to worry too much about it, but now that the weather is getting colder, my face feels tight immediately after washing it, and even when I apply makeup, dead skin cells build up, so it doesn't go on well. It's especially stressful because my cheeks and the area around my mouth feel rough to the touch. I make sure to apply moisturizing cream and even turn on a humidifier, but it only works for a short while, and my skin feels dry again quickly. I feel like my bad skin condition affects my mood for the whole day, so it bothers me even more. It's a recurring problem every winter, so I'm really struggling to figure out how to manage it.

Please recommend an ampoule or serum that is effective even with just a small amount!!