rehydrate after tanning?

This is my first reptile project and I don't believe I did things correctly. I received a rattlesnake where the client wanted a skin mount on a board. I used Rittel's snake tanning kit and followed the directions. I took it off the board after the tanning oil dryed about a week and was going to put it on another more decorative board. A couple of days later as I was getting ready to put it on the board, it had dried out some more and there is no stretch to it at all. Can you rehydrate it after it has been tanned so that I can make it look tighter on the decorative board or is this just a waste of time? Thanks for any info.

 

Thanks Redwolf. I was thinking that might be the answer but I didn' want to do it until I knew for sure. Now time to get busy..