Once You Know the True Meanings... - Vol. 1 Ch. 35 - The Back of My Eyelid

[MangaDex]

 

[MonstaMaps]

Clearly just been in Lavender Town

 

[TestAddress]

Certainly the girl lives in Kanto.

 

[ARealCoolGuy]

So... does the intruder have glowing eyes and teeth?

 

[ForTheJerusalem]

So... does the intruder have glowing eyes and teeth?

Uranium supplements baby!

 

[BakedBanana]

That thing in the last page looks like Something, is she about to dream of white space?

 

[juanan]

Somehow the darkness lump looks cute

 

[Yotomoe]

This one could've been better if the sillhouette in the last panel was more subtle.

 

[Arexty]

The medical term for the visions of lights and patterns the character sees when closing her eyes is called phosphenes.
You can induce them by rubbing your eyes as well which forcibly activates your retinal nerve cells (but don't do it too much).