Hmmm... if your snake is making consistent noise through her mouth (such as exhaling, whistling, clicking, etc) then that is a sign of RI (Respiratory Infection) and needs to be treated by a vet if in later stages. Now, an RI can be treated, if caught early enough, by upping the heat to 95/85 hot/cold side respectively.
A second explanation could be shes got stuck shed in her nostril from her last shed. Very possible.
If you see your snake start to breath with its mouth open, make clicking noises, etc. then you may want to take her to a vet.
-Andrew