I panicked and took her in to the hospital.
She was scoped - initially nothing to be seen, everything seemed ok so she was tucked into a stable and I left her at the clinic overnight.
This morning they scoped again and then did a skull X-ray. What they found was a large cluster of extra material where a tooth should be that is displacing her actual teeth and pushing them into her sinus and pushing them sideways.
Apparently this case is unusual and they sent the radiographs off to two different dental surgeons to get their opinion. She will need surgery to remove it, plus packing of some sort to help stop wave mouth.
I picked her up today and brought her home with antibiotics to help clear the area in preparation for surgery.
She seems in good spirits, although last week she wasn't too well. It must have flared up.
I just want her to be better again. Even the vets feel sorry for me - the poor horse can't catch a break!
Thank god I have the common sense to have vet insurance (although I think this will eat up the whole $2000 worth of cover for this year).