Dental abscess treatment

Our 14 yr old kitty has always had bad teeth.  We've had them cleaned once but because of age, not annually.  About a month ago kitty started to sneeze with eating.  Then started to have that third eyelid up all the time in one eye and face swelled up.  Took him to vet, who diagnosed an abscessed tooth with an open wound next to it.  She gave us 10 days of Clavamox and wanted to remove tooth / suture wound at end of antibiotic course.  

He had the procedure on Tuesday along with three other teeth removed.  Without asking us they did give him a Convenia injection, which I am upset about but what can I do at this point (since we had refused it originally I don't see why the vet did it this time, but it wasn't in his chart).  

Three days out.  He seems lethargic but has always been a big sleeper, not too playful.  He has to be encouraged to eat, prefers only to lick gravy, and sneezes and makes 'whuffing' noises when eating.  We have buprenex for pain meds, not sure if they are helping.  I am basically worried that he is not eating enough and on his own, and hiding and lethargic.  Is this just being traumatized from the surgery and residual pain?  The vet seems kind of not sure about his prognosis.  

Thoughts, similar experiences we can draw from?  

Sorry to hear your cat's had a rough time lately. His mouth must have been really sore. After the abscess and extractions etc he's had I'm not surprised he's still off his food. His mouth will still be pretty sore. I know mine would be!

If he's just wanting to lick, you could try liquidising his food, or maybe cooking some chicken and blending it with water to make an extra yummy soup for him.

Older cats can take a while to bounce back. Since he's still sneezing and seeming congested somehow it might be worth checking that the infection has really gone. He may need another course of antibiotics or something. I hope he feels better soon.

Thanks for your thoughts.  I get the feeling from the vet that the sneezing is some trauma from the sinuses being involved in the abscess, but it's not clear.  Would you push for additional antibiotics with the Convenia still in system?

Three days is not really that long for such trauma, the thing to do right now is not to worry so much about WHAT he is eating, just get him to eat SOMETHING! Even if it is tuna juice or his favorite food thinned down so he can lap it up. Try jarred meat baby food, my cats can't resist the turkey flavor. Is he peeing and pooping? He may have some diarrhea from the antibiotic and the trauma too, so make sure he is drinking plenty of water. I just had a tooth removed and know what the poor guy is going through, the oozing of blood can last for days too. All the luck and keep us posted, hopefully in a few weeks your precious baby will feel like a kitten again!

I wouldn't push without being sure it was needed, but if it doesn't settle over the next few days it might be worth a check up. Sinus trauma could easily account for it though. Give time for swelling to go down and reassess then. All I'm saying is keep an eye on it really. Sorry I didn't pick up on what Covenia is...We don't get told brand names of vet administered drugs for animals in the UK. I'm usually told antibiotics and it's left at that