He bites at one paw in particular and it is now bald and his pads look raw. It looks like it has been shaved. 
The vet said it is a sign of stress - I have bought feliway plug-ins, but we have been using them for a few weeks and he still sits there biting at his paw.
He has always done it.
Is there anything I can do to help him to calm down? He doesn't seem stressed in any other way, and is affectionate and a good eater (!) but this paw-biting is pretty awful.
(We are moving house for the second time in a year in a couple of weeks, so he will be facing some upheaval again, so if I can do anything which eases that, that would be good. But this is a long-term problem so I don't think the acute stress of the move will make it any worse than it normally is.)