Surgery under General Anesthesia makes skin smoother

Hi all, just wondering what in general anesthesia (GA) makes your skin so smooth after surgery? I am 23 and in the past 2 years, i have gone through 3 surgeries under GA and what I noticed from all 3 experiences are that my skin looks extremely smooth and firm after surgery. Don't get me wrong, i have oily skin and i put moisturizer before and after the op so my skin does not feel dry.

Any medical people here can enlighten me what's in GA that makes my skin glow and it being so smooth after op?