diana

I think I heard or read somewhere that people don't actually swallow spiders while they sleep, because spiders have an instinct not to enter wet, warm places like an animal's withins on the first place.

Your sleepless nights are still safe.

but what if one's just over you and falls off its web into your mouth, you'd have to swallow it right?

That story of 'everyone swallows like 4 spiders a year while sleeping' is fake and was used as an experiment to show how quickly fake facts could be spreak around the internet. Sleep well!