As he is losing weight you need to be properly syringe feeding him. He needs to have at least 60ml of the recovery feed per day (a healthy piggy would eat the equivalent of 100ml per day). Use a 1ml syringe (I find it easier to have multiple syringes all filled and ready so you don’t have to reload after every syringe. They can only take around 0.3ml per mouthful).
You use your daily weight checks to know whether he is getting enough - if he loses weight the next day then he needs to be syringe fed more during the day. You gauge how many feedings you need to do by how much he takes at each feed and how stable his weight is - ie if he takes 10ml per feed and 60ml is enough to keep his weight stable then you need to do six feedings a day. If he still loses weight on 60ml per day you increase it to 70 and do an extra feeding etc.
The guides I linked in on my first reply explain syringe feeding fully
Don’t worry about him eating the box per se - he is doing it because he needs more fibre and that is why you need to step in with the syringe feeding.
And yes I would take him back to the vet. His weight loss might be associated to the pain meds being stopped
You use your daily weight checks to know whether he is getting enough - if he loses weight the next day then he needs to be syringe fed more during the day. You gauge how many feedings you need to do by how much he takes at each feed and how stable his weight is - ie if he takes 10ml per feed and 60ml is enough to keep his weight stable then you need to do six feedings a day. If he still loses weight on 60ml per day you increase it to 70 and do an extra feeding etc.
The guides I linked in on my first reply explain syringe feeding fully
Don’t worry about him eating the box per se - he is doing it because he needs more fibre and that is why you need to step in with the syringe feeding.
And yes I would take him back to the vet. His weight loss might be associated to the pain meds being stopped