Help! My gerbil is sick/injured

Question
Help! My gerbil is sick! We have 2 gerbils, Tweedledum and Tweedledee, we think they are both females. One is fatter than the other, we call her Tweedledum (hehe), and the skinny one is Tweedledee.
So Tweedledee had something happen to one of her hind legs a couple months ago. All of a sudden she started dragging one. Her front paws were fine, as was the other hind leg. My next door neighbour works at an animal hospital. We took a look, and we were able to move the injured leg without her squeaking or seeming to be in distress. So as long as she seemed to be okay, not in pain, and eating, drinking and moving okay, we left her alone.

Well, now there is something wrong with her tail!! From what I have been reading, it seems to be 'broken tail', but this problem is at the base of her tail, reaching up onto the rump. It's hard to describe, but the base of the tail is reddened and hairless, and the rump is dark and the skin looks funny? From what I read, broken tail is caused by the tail getting caught in the wheel. Their wheel, (which we have now confiscated) is a mesh, too small for tail to get caught. Also can be caused by lifting by the tail (which DH says he has not done lately). Not sure how long she has been like this.
Can you help me? I have pictures if it helps.

Answer
Hi Katie

I'm not sure about this - I'm going to get some advice on it and will write back tomorrow.

Regards

Hi Katie

Wanted to check this out as most of my knowledge is with hamsters.

It is difficult to know what has happened to his tail.  Rough handling can cause breaks in the tail - especially if you are holding your gerbil by its tail and he is twisting about.  If there is a break, I understand this normally heals on its own unless there are any complications.  However, I do not know why his rump is dark and reddened.  I would advise getting this looked at in case it needs medication.

Regards