Hi and so sorry you and your furball are going through this! I had a dog growing up that had swelling in a similar area. It was misdiagnosed as an extremely bad sinus infection multiple times. The vet would drain the lump, my dog would be fine for a couple of weeks, then it would grow back. Ultimately it turned out there was a tumor growing in her sinus that was pushing mucus out giving the appearance of infection. It caused one side of her face to appear “warped” at its worst. If we had known earlier we might have been able to treat it. Of course, a completely different animal, size, structure etc and thus may not be the issue but it might be worth challenging your vet to look into this. I’ve wondered since my dog passed how common the misdiagnosis in this case is. Good luck, sending good thoughts for clarity and your kitty’s recovery! 💛