Recovery from bladder stones - What is normal?

Question
Hello,

I have two male guinea pigs, both 2 and 1/2 years old. This week we had a big worry with one of them, he seemed in a lot of pain, after an emergency vet visit an x ray showed a large bladder stone. They have been perfectly healthy until now so we have been very worried. The vet said the stone was too big so he would have to operate. Just before they were about to put him under, he luckily passed the stone himself although even the vet marvelled at how big it was so it must have been very painful. The vet was happy and sent him home yesterday. Although he is eating again, he still doesn't seem to be actively seeking food and seems quieter than normal. I have noticed that his poo is soft and smaller than normal. He doesn't seem in pain but not himself. We have been so worried about him, and I know his behaviour isn't normal, but is this just a reaction from being to the vet and some after pain (we've been given pain medication to give him)? I'm just not sure what is normal at this stage , don't want to take him back to the vet to check as that is distressing in itself and if it is normal it wouldn't be worth it. Any advice you could give us would be appreciated. What to expect now and how we can avoid the problem in the future.
Many thanks.

Answer
What he's been through is the equivalent of a woman giving birth to a 40 lb baby. Males are not anatomically built to pass large stones.

What he's going through is a recovery period from the extreme pain and stress. Get some Critical Care to give to him. It's like Ensure is for humans, filled with the nutrients they need to keep tissues healthy while under physical stress.  Continue the pain medication for another few days.

Offer him as much lettuce and melon type fruit as you can to help keep him hydrated. Hopefully he will return to his normal self within a few more days.