Maybe it's the late hour, but I'm having trouble imagining how your snake could "pinch" such a small area on her body, but I suppose it's possible.
Snakes do some peculiar things in spite of being fairly slippery...but keep an eye on it (I know you will...) to see if it gets larger or looks worse. It
looks more like those scales got folded back, while going thru something snug. (is that what you meant by 'pinch'?) Probably nothing to worry about.