darken highlights in a dark scene

Hi group, I'm in a directing workshop at UCLA and I shot a bedroom scene at night and the shot is under exposed 1 stop shot on the 5d and XF100.

Wondered what the best way to darken the bedsheets might be.

I'm having a hard time figuring ways to do the corrections as I would being a still photographer, not used to gamma, lift, and creating masks.

Is creating a duplicate layer with a mask and some blur the correct method?

Thanks David