Depending on what you are feeling, your facial expressions change. Your personality type will express emotions differently than other types.
The core emotions are passion and shame - satisfaction and anxiety - fear and courage - and anger and peace.
When an INFJ experiences anxiety, shame, anger, or fear, these expressions will often come out from their inferior functions and from areas associated with these functions.
When an INFP experiences passion, satisfaction, courage, or peace, these functions will come out from the INFPs natural, dominant functions and muscles in the face associated with these functions.
An INFJ will express satisfaction through pulling down and activating their chin muscles, signalling relief and a higher understanding. An EXTX would rather seem anxious or uncomfortable when doing this.
An INFJ will express passion through using their upper lips, broadening their smile widely and their smile will be passionate where an XXTP would rather seem dispassionate or ashamed when doing this.
The INFJ will, when angry or in disharmony, concentrate, tense and focus their brows, using ESXX. An ESFP who did this would rather look peaceful and harmonious when doing this expression.
The INFJ will, when fearful or uncourageous tense up the muscles around the outer part of their eyes, shielding their gaze somewhat, and making them look high on adrenaline, restless, and unruly. An XSXP type would rather look energetic and courageous when doing this.
When an INFP feels high on courage and bravery, they tend to activate the muscles around the outer parts of their eyes, signalling curiosity, flexibility and eagerness to learn. When an INFP feels at peace, they will have a natural, amused, understanding squint.
When an INFP feels anxious or uncomfortable, they will typically tense up their cheeks, creating a kind of helmet to protect them from their environment. If the INFP also feels shame or dispassion, they will tense up and activate their upper lips, adding a visir to their helmet. An XXTJ would rather look positive or passionate when activating their upper lips.