[Her clinging to him like that reassures him enough to smile a little, though it's more subdued than it was before.]

Don't worry, I'm not. But I am going to need to get up for a moment.

[Then, quickly, to let her know that it's not because of her in the slightest:]

I need to take this off, and I'll get you something to clean up with. I promise I'll be right back.

[... in a moment. Because that requires moving, and moving requires muscle coordination, which is something he's rather lacking right now.]