Prompting unselected pixels means that the selected location is blank or edited in other layers. The following is a method of font thinning:

Required materials: PS.

First, double-click the blank area of the rasterized text layer to open the layer style.

Secondly, check "strokes" in the layer style.

Third, set the brush stroke color as the background layer color.

Fourth, the position is set to "center". Finally, just increase the size a little and click OK in this window.

Five, the effect is as follows, the above is the original picture, and the following is the refined effect.