I can see how you would be double guessing the vet's advice. Looks like a good owie she's got going there. What if you, instead of washing it, put some Neosporin or other antibiotic treatment on it. I don't know if that would work so good though, because she can lick it off.

I think at the very least a call to the vet would be in order, just to see what they advise.

Hope your little tail heals real soon sweety Ebby.