My senior kitty Onyx, who is 15, recently (a month ago) had his rear left leg amputated to halt the spread of cancer in the joint. He was previously a very healthy cat, if a bit overweight. He has recovered fairly well from the surgery and is decently mobile. I am a bit concerned about the fact that his fur is not growing back where it was shaved. It is his entire rear left quarter that is bare. He has also started noticeably losing whiskers. He does not appear stressed, in fact he seems more 'kitten like ' than he has been in quite some time. His appetite is good and he plays, and wants constant affection. Two nights ago he was on my lap (as usual) and when he tried to stand to adjust position, he growled. It happened a few times. Later when I tried to put him on the sofa beside me to get up, he growled at me. There haven't been any more instances of it since. I'm just wondering if there is anything I can do to speed the hair up in its growing, I worry that he gets cold as it's a large bald area, and I am concerned about this sudden whisker loss.