Red marks around mouth

My lady Pastel as some kind wound on her mouth an l have no idea what it is. I am changing bedding(newspaper) every two days (and just after dirties it) but after a week it is still as red...
I checked everyone else and none of the other have anything worrysome to them.
http://i906.photobucket.com/albums/a...psu04brwcw.jpg
http://i906.photobucket.com/albums/a...psujqbyuor.jpg

The best option will be to go to the vet but if it can be taken care of without that would be splendid.

Do you feed live or F/T? And just to be clear, we are talking about the reddish spot to the right of her labial pits, correct?

bite or a bad rub is my guess i have to re ask do you feed live?

Looks suspicious for a bite wound. Maybe a foreign body like a piece of substrate that became imbedded in the mouth and or gumline.

It did appear after her last feed...

I feed them all F/T and it was the first time she was fed with me. She did not leave me the time to drop the rat and she was already at it. That would explain why she was not interested to bite after the first try. She might have caught the tongs and hurt herself then D:

She does not make more annoyed movements when I touch it, would I suppose it's going to go by itself in a few sheds? Is there something I can do to make it less hurt if it does still hurt her?

Sorry if I missed it but have you looked inside her mouth?