That is called Hypoxemia. Hypoxemia<span>s a sign of a problem related to breathing or circulation, and may result in various symptoms, such as shortness of breath.</span>
I would say feelings of worthlessness. You can't really see it on their body, but they can tell you if they choose to, so that makes it hidden in my opinion.
I hope that helps!
1. Tell parents or trusted adult.
2. Call hotlines
3. Pray to God ( My opinion )