Euphie our injured Cat

Our cat had a hard week. Last sunday I noticed he was franticly licking his tail. I could see there was a wound were his tail meets his body but he would not let us get very close. I could get close enough to see puss and a very swollen area. Euphie has always been an inside cat until we moved into our first home. Our hose seems to attract many strays and other neighborhood felines. Often the come up to the bedroom window at night and harass poor Euphrates. Anyone who has cats knows that it is impossible to keep them indoors if they want to get out and defend their territory. There has been a particular stray hanging out at our place, a young little cat that plays with Sam, and makes Euphie very irritated and jealous. There are other larger cats that I have seen Euphie fight with. Our cat is six years old, no spring chicken, while he still kills mice, moles, and unfortunately a few birds he does not fair to well in any cat fight.
Took him to the vet on Monday, turns out he has a single very deep bite. It was infected and a large abscess. It required surgery and I have had to give him antibiotics twice a day plus hot compresses. So far it has cost us over $200. Since Euphie does not have a flexible health care account, he was been informed that he is once again an indoor cat. Now that it is getting colder I hope it will not be too challenging. Euphie actually seems to be basking in all the attention.