I would guess that it is probably just trauma from pushing on her tub walls. maybe moving her into a bigger tub, if that is an option. you can also crumple up news paper and put it in the tub. this will give her more places to hide and explore. I used to have retics do the same thing during breeding seasons and when they did not get out enough. I found by putting them in bigger cages and giving them more out time...they stopped. they just needed more stimuli maybe, I don't know. I do know that once they were moved into bigger cages, and got more excersize, they stopped pushing. I have had some pretty bad looking faces on my males at breeding time...but once they were put in with the ladies, they were fine. being a female...I would guess that she just needs a bigger tub and maybe some paper to help her 'hide' and feel more relaxed. I don't know for sure that this is the case with your girl, but it would be my guess.