system
Given the following post, respond as if you're commenting on Reddit:
human
[Stranger Things] What's actually happening when El bleeds while using her powers? (plus related spoiler question)

I am not acquainted at all with the medical field. We see this in fiction with anyone using mind powers all the time. Are blood vessels bursting? Is her brain hemorrhaging? What's up with that? 

(spoiler question follows) 

Is she didn't sacrifice herself at the end, how long realistic could she even expect to live? What with constantly bleeding from all her face holes.
gpt
Children and adults with high blood pressure, and stress, exhibit nosebleeds. There is a blood vessel in the nasal passage wall that has only a thin mucosal lining above it. If it bursts, it bursts the mucosal lining as well.

It may also be due to her ability to shift between our world and The Upside Down, in that small portions of her body may be lagging behind the remainder as she shifts.

Frankly, Director, we'll need to find another candidate for development to find any hard answers.

*opens dossier*

The surveillance of the missing boy's mother turned up an instance of an infant girl who had a Close Encounter in the residence at the reported Thin Wall. *That* child's mother's narcissism index is significantly high; she'd be amenable to a Magnet Programme approach.