Tiny otto cat: I'm so sorry- what to do?

I put three small otto cats into our main tank about a month ago and
they immediately went about the business of cleaning the algae from all
surfaces. Last week I found one dead, way in the back behind a
decoration. It's such a hard-to-see spot and these guys are so small
and elusive that he may have been there for a while before I spotted
him. He seemed a bit long-dead.

This afternoon, just half an hour ago, I came home to find another otto
cat jammed into the intake slots of our filter tube, hanging
motionlessly. Over the months, this is where I've found most of our
small handful of fish losses- I assume that they drift lifelessly and
end up being pulled gradualy towards the tube. So I reached into the
tank and pulled the cat out from the slots- he was really jammed in
there. When I brought him towards the surface though, he wiggled and I
let him go.

He's alive, but I've hurt him by pulling him out of that slot and I am
honestly so f*cking sorry right now because of what I've done. He's
trying to cling to the glass, and sliding down. Then he swims
vigorously, but in circles- I've damaged his left eye somewhat
noticeably. Should I just let him be and keep apologizing to him while
hoping that he can recover, or what?

I hate this feeling.

--
Ian.