I drew some Orovoro faces, I'm not fully satisfied with them just yet. Figuring out coloring them right will be important because the species emote using chromatophores. These pictures are already wrong because I've decided to not have them use facial expressions at all.
Black: Aggression-Hostile
Yellow: Fear, Stress-Immediate
Green: Happiness-Satisfaction
Blue: Happiness-Excitement/Arousal
Purple: Laughter Equivalent
Brown: Stress-Ongoing, Illness, Exhaustion
Gray/Tan: Tiredness, Boredom
Pastels: Severe Intoxication
White: Seizure/Medical Shock
They usually turn a blotchy mix of green, gray, and tan when they are asleep. Red and Black are different because Red means aggressive as in "competitive/dominant" and Black means aggressive as in "might commit a murder".
Green, Tan, and Gray are their usual colors, while other colors typically don't appear for more than a few minutes at a time. These chromatophores have different expanded/contracted defaults. When an Orovoro suffers from a seizure or goes into medical shock, it causes all of their chromatophores to contract and turn their skin a semitransparent, milky white color. An Orovoro can contract all of its chromatophores deliberately, but this is usually only done while undergoing medical checks to help their doctor examine their veins and organs.
Orovoro can control their colors deliberately in much the same way that a human can ontrol their facial expressions. Some being better at it than others.
