Normally I would post something of this quality in a sketch dump, but it's such a different mood from everything else I've drawn recently I decided against it.
So this OC that's appeared twice before, temporary name Sinnan, has a mentally lethal combination of misphonia (a selective sensitivity to sound, literally "hatred of sound") and tinnitus ("the perception of sound within the human ear in the absence of corresponding external sound")
In other words, she hears a ringing in her head and it drives her mad.
So here she is in the deep waters, trying to escape the inescapable sound.
Homestuck (c) Andrew Hussie