if she has mouth rot you may hear some squeaking or whistling type noises when she breathes. it may just be every once in a while--not every time she inhales or exhales. she also may rest with her head upward as opposed to laying flat in her cage. i had a bp with mouth rot and she would prop her head up on the side of her enclosure and i could hear her whistling occassionally as she exhaled. i don't remember her mouth or tongue being discolored though. is your snake due to shed soon? her tongue could look duller in color due to that.