Oh, don't get me wrong. The sprite itself is good. I can see how you could get attached. It does seem pretty cute.
And I think the thermometer itself is a good size. I think the issue is more so that it diverts my eyes too far away from the character I'm controlling to look at it, especially when the two are on opposite sides of the screen. Not sure if there's an elegant solution for that though.
First idea that comes to mind is the way games like Splatoon handle it with incorporating the meter into the character design, but I'm not sure if that would really work for a sprite game, especially with sprites of this size. Having it follow the character might also work, but that comes with its own downsides. Incorporating sound design does seem like a good start if nothing else.
I didn't even notice the shivering and other effects my first playthrough. That sounds like it would be a good solution as is, so I'm not sure if it wasn't noticeable enough or if I just wasn't paying enough attention as I played. I'll have to look out for it the next time I give it a shot.