Update: Pleco's gone now and I've been keeping up with the water changes and all.
I'm on day 10 of Lifeguard treatment, as it said to give a break for one day after the 5th day...and well...
My betta looked like he WAS improving, but in the past day or so he's been either really listless and lying around and hiding, or he's been swimming the tank like mad, he also has been darting in and out of the plants like he is itchy.
I've also noticed his lateral line has turned almost a light grey/white, his belly has turned white and his eyes are still partially cloudy. He is eating off and on, but today has barely touched anything, and he's refusing to flare up even with encouragement from his favorite color, and his fins are still super droopy.
I'm super confused and really concerned, I don't know what else I can really do for him.