Please help Frodo

Frodo Baggins is 8 years old and the most loving cat in the world, we saved him from an unhappy life 4 years ago and hes well and truly part of our family now.  He loves to go outside but never far from the house and has never been hurt or poorly, but today we can see a large lump has appeared on his cheek which he wont let us touch, and a tiny wound just beneath the swelling, his eye is half closed and watery. We're guessing hes had a fight and now has an infection though at present he doesnt seem to be in pain although he flinches if we try to touch his face which is heartbreaking, but he's sleeping a lot and off his food. We have accident insurance for him which I naively thought would cover all vets fees but sadly not, and as myself and my husband are both on reduced hours due to the pandemic we cant even afford a consultation at the moment, and from a lot of googling it looks like it will lead to antibiotics at least, if not an operation to drain the abscess. We are both trying so hard to find the money to help him but would appreciate any help you can give so so much. I hate asking for anything and have never done this before so apologies if I mess up but please if you can help us help Frodo in any small way we would be so grateful. Thank you.