Dear Iain,
 
My name is Mojo, and I had a swollen behind after I came home with Kim
and Scott from the ferret farm.  I was only 8 weeks old and was so
small that I couldn't hold my rear up from the litter when I went to
the bathroom.  It was red and swollen to begin with, and when I pooped
litter stuck to the sore part, and made it worse.  Scott bought me
some soft wood shavings for the litter box while I healed.  My big
brother Oakey wasn't so happy about the fluffy litter, but it was only
temporary.
 
They also called the ferret farm and asked for advice on how to make
me better.  The ferret farm told them to dab Preparation H on the
swollen area after I used the litter pan.  Of course, they made sure
the area was clean and dry first.  They held me for a bit to make sure
that it had a chance to work before I tried to wipe my butt on the
ground.  It smelled so bad that I didn't try to clean it off myself.
 
The Preparation H made my butt pink again, and after a couple days it
wasn't swollen anymore.  My butt has been better ever since...
 
Mojo
 
Note from Kim: I didn't run this past a vet first but it worked really
well for us, and was an inexpensive solution.  I'm not sure it your
ferret has the same thing Mojo had, but it may provide some relief!
Good luck!
[Posted in FML issue 1125]