OMG I am so sorry, all my condolences RIP Juliet and Romeo. I am sure they are very happy to see each other again in Cats heaven. You and Romeo and Juliet are in my thoughts.
Thanks everyone for the support thus far!
It's been two weeks and I brought him back to the vet today. I've been giving him medication twice a day and unfortunately the vet said his wound is still only half way recovered.
So, here's to another 14 days of struggle to get Derby to take his medicine. But it's definitely worth it.
Oh, and I took a picture of him at the vet, I'll attach the photo :]