You might try this, even if you have to wrap her in a towel: Lift the upper lip at the REAR of the jaw...there's usually more space there to squirt the stuff in from the side, and you don't have to pry the jaw open. If you CAN (I know this may not work) don't give her the whole dose - allow time for swallowing AND breathing between squirts.

Have treats ready for afterwards - right away!

Good luck!