What Is Going On With This Part Of My Scalp [pics Inside]

[big bill hell]

Lately (as in like, 2 months) Ive had heavy shedding out of nowhere, and my normally thick hair isnt quite as nice as it used to be in one part of my scalp. I'm curious as to what this could be and ideally how to stop it (if at all possible) Hairline has stayed the same for what its worth - minor shedding on other parts of the head but mostly centric around here.

Any help is appreciated, thanks!