if she is young enough to have her ears done she is too young to worry to much on bulking up , that comes from genetics, exercise { which you dont want to over do with a pup } and age { they bulk up and fill out i find after the 1st year and can up to 3 years } Unless you mean she is skinny and not eating , but if she is gaining weight and eating then thats all that matters with pups, gotta remember not all dogs grow the same or have the same bloodlines so comparing her to another dog of the same breed even is pointless.
As for the ears , your vet will offer the info as to what to do I have notcied some vets offer different advice then others so follow what your vet advises. Pain meds are usually sent home with your dog and you admininster 2x a day or some 1x day { again whatever your vet tells you} she will also have a cone to keep from scratching the stitches , my advice is grab an extra one while your at the vet lol { 1 of my girls went through 5 cones while the other went through only 1 but it was pretty tattered at the end lol} she will usually be pretty lathargic for the 1st day home but energy quickly recovers with the pups and by day 3 or so they are back to there feisty troublesom selfs , I think by day 10 we were getting stitches removed so healing is fast. just remember what you see when you pull the tape off for the 1st time isnt the end result it can take months before the ears sit like they should , post up after the crop and after stitches are out and if needed there is a good thread about taping if you should need it.