It depends. If the mouse is looking to bite the snake, then obviously not long. If he doesn't look interested, he probably won't be.

What are the temperatures and humidity in the cage. What type of cage are you using, tub or terrarium. Also, is your cage full of stuff or too empty?

Going one week without eating isn't a problem.
You should just let him settle for at least a week or so more WITHOUT handling him before you try to feed him.

Your cage could also be too large.