Sorry about your little one. I hope things get better soon for her.
My son is only 5 months so we have yet to go through the teething stage, but I have heard of putting (clean) wet wash cloths in the freezer and then letting her gnaw on them.
If you have a mesh feeder, you could put a cold, refrigerated piece of banana or other soft fruit in it for her as well.
Best wishes to you and her