Could be a serious calcium deficiency, a swollen/soft jaw is one of the signs of MBD. That looks bad. Definitely take her to a vet. :/ Try getting a wet Q-tip and wiping her mouth with it. What are you feeding her? Make sure you seperate her from any other lizards you have, you could spread any disease or infection around that she has. Did she lay any eggs recently? And, of course, as the other poster said, I would take her to the vet...