Having lived with a headtilt bunny for four months now, I can safely say there is no chance of overreacting when it comes to this disease. But you say she can straighten her head: is she walking in circles? Are her eyes darting back and forth? And does she seem unsteady on her feet?
Pip is a head tipping bun and more than a few times I've feared she was developing head tilt. But she just naturally does this or from time to time she gets excessive ear wax on one side and that will cause her to hold her ear/head askew.
Your best bet is obviously to take her in for a checkup. But that has to be your decision. Mimzy went from mild spinning to 90 degrees tilted in one hour and his head hasn't gone straight since even though he is as healed as he will get.
I'd keep an eye on her for now and if you see it getting worse I'd bundle her up and go. For me though when there's any doubt about my bubs' health I get them in straightaway. Better safe than sorry.
I hope Lady Mimzy is just being silly though. Sending stay-healthy vibes!