Thanks for your question regarding your 11 year old girl Chloe who seems to have a relatively large wound on her behind! The poor girl. It is hard to say how this could have happened if she is purely an indoor cat. If she was an outdoor girl, it would be a high likelihood this was due to a cat bite abscess - however as she is indoor only, this is more likely to be due to trauma some how.
Given the wound looks pretty deep, I would definitely encourage you to get her seen by your local weekend Vet tomorrow morning if you can. This isn't urgent so long as it isn't bothering your girl and isn't bleeding. If you can get her seen tomorrow morning, the Vet can decide whether this can heal as it is (along with an antibiotic course if necessary) or whether it needs to be freshened up and stitched. If it looks relatively deep, then it may even need a drain placed in to it to help reduce the chance of infection setting in.
For now, try and keep Chloe as quiet as possible. If the wound is weeping or dirty, then gently clean it with some warm salty water (one teaspoon of salt per cup of warm water). If she is licking the wound excessively, you will also need to get a collar cone from your local Vet tomorrow.
Best of luck with this girl and please do get her seen in the morning if you can. Don't forget to click an excited face :-D if this has been helpful. Please be sure to reply using the REPLY TO EXPERT
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