One heck of a tooth problem.

Question
I've had my two female rats for about 6 or 7 months now. They've always been in excellent health; but now, the elder of the two is having a tooth problem. Three of her four incisors are at proper length, but one on her lower jaw is much longer and is causing the left side of her face to swell, and is even secreting the red fluid from her nose. Should I go to a vet and get them to file it down? I'm at a complete loss as to what do to.It doesn't seem to affect her eating/grooming habits, but she's not as active as she was before this problem arose.

Answer
 You'll definitely need to take her to a vet.  If the tooth isn't properly aligned it will have to be trimmed every week or two for the rest of her life.  It may be that she has developed an abscess in her face that is causing the tooth to be misaligned, and with treatment her tooth may come back into alignment and she will be able to file it on her own.  If it is in the proper position but it is too long it probably is due to an unrelated problem in her mouth and the pain of bruxing her teeth to the proper length is too great for her to keep it short.  Your vet will be able to take a look in her mouth and determine what the problem is and what can be done about it.  I hope she gets better soon, good luck!