I have been victim of this. I got a 22 LR ruger single six for Christmas one year and put my hand around the cylinder without thinking about it for extra support. Fortunately with a 22 LR it is not as bad, but it hurt and burned. Glad I figured that out before getting ahold of my 45 Colt and 44 mag... I was pretty young at the time.
I did this with my S&W 629 .44 Mag when I was younger and more ignorant. By God's grace, my hand is intact. I had some mild burns and bruising for a few days, but never broke the skin.