I think he's going vigilante style so he's covering his face. Are you referring to the last page? It doesnt look that way to me. Look closely, the right eye isnt closed.
Yeah, it's the last page. I looked, which is why I'm suspicious. Right panel only shows his left eye and then the right panel shadows out the right. That's normally a hint that he suffered a permanent injury.
Nah both eyes are fine. In the very last panel where he says “this is my power” you can see both eyes are open, the other is just covered a bit by his arm
Deku's right eye is first hidden and then closed.
Did he lose his eye, is that why he's finally wearing his cowl?