hi utpal

yes i would skin the proxy mesh, not the smooth. that's the whole idea of proxy skinning.

try using the hypergraph to reconnect the proxy mesh back to your smooth. Ctrl+drag the node to try to get it to connect with default attributes, if not, the connection editor will open. if that still doesn't work then i don't know ... just recreate the proxy i guess. It wouldn't take long at all...

good luck!

cheers