Well, it appears to have faded down now, although I'm still feeling some after effects.
I was wondering why my eyes felt odd. They're rather unshakeably dilated (the irises are sitting at about 2mm width from pupil to edge, while the pupils are over a centimetre wide - it looks rather scary and unnatural up close).
The minor headache I got from my crown chakra going all weird is sort of down to a small twinge now.
And all four chakras are still open, just not so strong that the chains between them feel like I'm actually wearing jewellery (the crown-to-third-eye chain actually felt like it was some sort of hanging pendant, coming down over my forehead and resting on the third eye). Apparently I can amp them up if I try too... but I really feel like getting some sleep now, since I kind of need to recover from the mere two hours I had last night.
Edit: Except that it's damn hard to sleep when you have 4 to 5 chakras buzzing.