Post castration surgery

Question
Hi,
I was wondering if you could put my mind at rest.  I've had my boy castrated 3 days ago (due to excessive aggression to cage mates) and he's showing some strange signs.  His back legs are still wobbly, he is using them - running around, scratching, cleaning but then when he'll have moments when his back legs just give up and he does this weird stretching out crawling along the ground movement, then drags his legs up again and acts normal.  This whole repertoire last say 5 seconds a time.  Also, he has a concaved stomach, before the op he was a normal healthy rat (550g) but now where his rib cage ends it just dips in quite a bit and you can feel his backbone, it's like muscle wastage has set in (he's only 7 months).  He's really miserable but I suppose that is to be expected.

I saw this behaviour straight after taking him home from the op, I then rushed back to have him checked out again.  The vet said he'll be wobbly for a day and he hadn't lost weight so it was probably nothing (he's eating and drinking fine).  3 days on and his legs are only slightly better, but stomach is the same.  I can't seem to find anything about this on the Internet and my vet isn't being too helpful.

It would be great if you could shed some light on what you may thing is up with him, could they have damaged a nerve? and is there any reson why he is all of a sudden skin and bones?

Thank you for any help

Answer
Sounds like he is in pain.  Please tell me he was given a pain medication and not  just an antiflammatory medication that has been known to kill pet rats due to liver failure, which the name of that drug is called METACAM.

Also, the vet.....how much experience does he or she have with rat surgery?  It sounds like perhaps his stitches are just so tight he is in so much agony.

I would find a new vet to take over, to be honest.