In Photoshop, you can use ArcSoft Portrait Plus 3 beauty filter to slim your face.

The method is as follows:

① First install ArcSoft Portrait Plus 3 filter.

② Open PS, import pictures, and call this filter-"Filter" in the menu bar. As shown in the figure:

(3) After the filter is turned on here: a) Select the preset-"Ordinary Skin Rejuvenation+Face-lifting". You can make the characters' faces smaller. As shown in the figure:

B. If you feel that Method A is not very satisfactory, continue to click Edit-Beauty-Face-lifting. There are three options: low, medium and high, which can be adjusted manually. As shown in the figure:

In this way, the character's face becomes thinner.