Having incisors 'cut' can be done 2 ways as far as I know: burring (with something like a little dremel tool and a very solid pair of hands to restrain that pig!) or clipping. Clipping actually isn't ideal as the pressure can cause splitting of the teeth but that's not inevitable - it's just something to watch out for if you got clipped and lots of vets still use this for pigs and rabbits too. Both methods can be done rather too short (so food slips back out of the mouth or they struggle to pick things up) but again that's not actually a massive problem as those teeth do grow very fast. Ivy got burred down after a few weeks - she looked very gummy and very cross as the vet had actually caught her lip which puffed up. A couple of days later her swelling was down and we were already seeing the teeth were longer. But Ivy's incisors were not bothering her originally - they just got too long when she stopped eating for other reasons.
Too-long incisors can impede chewing but I'm not sure about causing pain. When we've had a broken or infected incisor that has caused pain but when Ivy's got too long it was awkward and uncomfortable as she tried to chew but that was it. She chewed much faster after they were done, but it didn't cure her. There have been forum pigs missing one or even both (bottom) incisors that have managed well, but they do have to 're-learn' how to eat with their new mouth (for those reasons above) and confidence can be an issue initially. It sounds like your vet is thinking that the incisors were the obvious problem and your boy shouldn't therefore be in any pain and he'll get back on the horse - so to speak - when he realises he can. Long incisors are certainly an obvious thing to pick up on, but did that prevent him/her from looking a bit deeper? If they're right that's great - your issue is going to be if they're wrong and the overgrown incisors were, as in Ivy's case, just something inevitable when piggy is not biting and chewing independently for a while.
I'm assuming you didn't have a general anaesthetic then... so did the vet give him a good all over exam? Did they mention about the gut stasis or pain? Did they say if he'd lost any weight (has he?) or did they ask you about his weight? We can't tell you to go against vet instruction because it's against the forum regs and rightly so. What I can say is that personally in my 10 years of piggy keeping I've
never seen metacam or loxicom interfere with appetite in a negative way (tho I have seen opioid painkiller prevent eating so I'm a bit wary of that). Pigs in pain eat less or stop eating - even if it's a general pain and not a specific mouth pain - then pain relief like metacam will encourage them to eat and keep their strength up. Even when my fat girl got bloat she got metacam as bloat is very uncomfortable and you'd think that digestive issues might warrant avoiding anything weird being put into the guts but no, vet said good old metacam will help her feel more comfortable and encourage eating the syringe food and it did. Old George is nearly 6 now, 1.3 kilo and on 0.3ml of 1.5mg/ml dog strength metacam
twice a day for his arthritis, and has been for nearly 2 years and it has never affected his appetite as his weight shows. So I'm thinking the vet must have felt very secure in his diagnosis that pain relief would be irrelevant in a couple of days but I get the sense that you aren't so sure yourself because you've seen how your lovely boy has struggled. If he doesn't start eating while on metacam I can't see why he'd suddenly start if you stop giving it. Do you happen to have enough metacam left for more than the next couple of days...?
You are in Vancouver, right, so presumably there are other veterinary options available...? I have to say that in your shoes I'd be thinking now about my options because until Truffle eats on his own - even if that's just a bowl of sloppy syringe food - you're still in life-support mode. If your vet felt that a follow-up was necessary to check that diagnosis was correct then frankly 3 weeks is a
long time: 3 weeks of round the clock syringing is a big ask for both you and Truffle because that's where things would end up, wouldn't they. If they'd said "come back Friday" or "phone in if no change in a few days" I'd feel more confident. Right now I'd be feeling not so confident - but still prepared for a happy turnaround in Truffle's condition. If it was just his incisors he would start to improve as he realised he could eat without pain or discomfort. Maybe start with little pieces of soft cucumber middle as they can just be slurped up. If you offer bell pepper peel off the skin and offer tiny slivers at first. Soak some food pellets in water and offer those because they can also just be slurped up. Nothing too hard like carrot, or too tricky to handle like lettuce as they have to sort of origami it into their mouths. And keep up the syringing - you won't kill his appetite by support feeding him - if they feel well enough to eat independently they certainly will, no matter how much we feel we've stuffed into them.
Would I personally be phoning round other vets at this stage and trying to get an appointment for the end of the week? Trying to find a vet who is piggy savvy, or keeps their own pigs so you feel more confident about their piggy credentials? Or maybe contacting any local guinea-pig/small animal rescues and finding which vets they use - because they would be seeing pigs on a regular basis with a range of health problems. Well, I'm a belt-and-braces sort of gal, so I'd have to say I probably would...
I hope your vet can help him in the long term x
Have a look at our syringe feeding guide which was been linked above, it really is helpful.
So 11pm 
I feed him on my kitchen table which is beside his cage and his brother feels close to us… he gets up and eats too. But I feed at 
