Most always tail rot is caused by excessive
moisture/humidity in it's cage. Do you keep water
in there? If so take it out. Also be sure to clean all
poop and urates daily and wash any soiled rocks,
vines etc as often as reasonable with a bleach/water
solution at around a 1/10th bleach to 9/10th water mix.
Let air dry for a few hours then hose off. Re install
when dry.
If it is indeed tail rot,
take it off any substrate (ie, sand,seed etc) and replace it
with paper like butcher paper, newspaper or what ever
will easily cover the bottom of it's enclosure. If after a day
or two the paper is somewhat messy to clean then simply
replace the paper with fresh paper.
Give it a good warm soak to make sure the tail is clean
from feces or grains of sand or whatever. You can even
brush it with an old/soft toothbrush which usually works
great.
After the soak, dry the uro off really good ... especially
the tail. Mix a betadine/water spray solution to about the
color of light tea. Spray the tail top and bottom thoroughly.
Don't dry it just place the uro back in it's enclosure on
the paper and make sure it's temps are up to snuff. Do
this every couple of days making sure that when it's put
back that there's clean paper for it.
If you see no change for the better say within a week,take
it to an exotic vet who is familiar in working with uros. It
may need antibiotics to aid in stopping the infection.
Good luck,
John