Rubbing nose raw

[Jrich]

I recently bought a 2 year old female Mbk at a reptile expo. When I bought her the seller told me he had just brought her out of hibernation to explain why she was a bit on the thin side and because he didn't plan to breed her anymore. I have her in a 20 gallon glass tank with 2 hides, a climbing branch, water dish, hot spot of 90 and cool spot of 74. For the first 2 weeks all was well and she had a very strong feeding response. I've been feeding her two adult mice once a week to start out before I move onto jumbo because two adult mice hardly put a lump in her stomach. Now she has begun to rub her nose so much on the glass that it has created a spot on her "nose". It's not bleeding or an open wound it's just discolored. Any reason for this besides just trying to get out or boredom? Possible solutions?