This seems peculiar...

[Will0W783]

I have a set of speculums of varying sizes for opening mouths, but I've heard a credit card can be quite useful. Just grasp behind the head very gently and firmly press the card/speculum/pencil/whatever you choose to use into the mouth from the front. I use it at a slight angle and kind of roll the mouth open. I have never tried this technique on anything other than an adult snake though, so I would be very careful not to crush her neck or break her spine while forcing her mouth open. I know you have a baby hognose- I would honestly just wait and see if she is doing it tomorrow. I would err on the side of caution and wait to force open her mouth as long as possible, but that's just me being nervous about hurting any of my snakes. If you are very very gentle, it should be fine.