Hmm, that is very strange. It’s a slow, exaggerated jerking motion. Almost like she is losing her balance or feeling dizzy. You said her face is “pinched”. What do you mean by that exactly? Does she have facial paralysis on one side? These could be signs of an ear issue.

I agree, maybe an ear issue?  It almost looks like hiccups when she brings her head back around, so maybe stretching back to clean like that affects her breathing further? A chest xray would be an idea..

She looks like a small, dwarf rabbit. Has she had any teeth issues? Sometimes the molar roots overgrow then cause various issues (respiratory, ear infection, face abscess, infection behind eye, bony changes to face etc). 

My lop has a hemifacial spasm that causes one side of his face muscles to stay contracted. We think it is from damage to a cranial nerve. He has an abscess that affected his ear.   This is what it looks like –

  This is another image from medirabbit.com showing the asymmetrical face, due to paralysis.

Source:  medirabbit.com/EN/Neurology/Differentials/facial.htm

Is Pepper’s face anything like this?