How can I remove this stain?

I have just had new windows put in with lovely mahogany sills and surrounds. I haven't had a chance to seal the wood with varnish yet, but due to some work being done in the living-room, an incredible amount of condensation has run down my window and left a horrible big water stain on my new sill. (I didn't notice the condensation because the window had a cover over it to protect it!- ironically!) Is there ANYTHING I can do to remove this stain or am i most likely going to have to get it replaced? Any advice greatly appreciated!