hey sweetie...i'm sorry you are so upset. it is so sad when they aren't how we think they should be after an injury. maggie got her cast off a couple of weeks ago and is just now starting to use it all the time. for the first week, she would not use the leg AT ALL. she let it hang all the time. the second week, she used it more, but not much. now she is pretty much using it all the time. she will pick it up occasionally.
i am sure he will be fine...give it some time. if he isn't using it more in the next week to 10 days, definitely go back to the vet. if you feel like something might still be wrong, take him to another vet for a second opinion.
oh, and as for the sores, maggie had those too. she had a cast for 8 weeks so we had a lot of sores to doctor. it is normal, from what people tell me. just keep some neosporin on it. it will not hurt him if he licks it...but if you are concerned, put some neosporin on it and then put that cast cover i made for you back over it. you dont really need to do that, but if it helps, then go for it. the sore will heal really quick..i was shocked at how fast maggies healed!!!
pm me if you need any help or if you have questions. i drove my dr's nuts asking questions during maggies cast time
actually, they were GREAT but i was in there quite a bit
bless his heart...