Oh, I feel your pain! Quite literally. I've barely been riding this winter, and after two consecutive days commuting I'm beginning to wonder what I ever saw in cycling.
My experience is that 6 weeks or two months off is enough to make starting again painful. On the other hand, after a week of daily or almost daily riding it does go away, for me. It's also by far the most painful the first ten-fifteen minutes, if I can grin and bear it through that it gets better again.
I'm talking about bruising, that is the tender feeling you get from pressure directly on your sit bones, NOT chafing or a too narrow saddle. Any sore skin or numbness you need to look at your saddle set-up. 160 sounds wide enough. A too narrow saddle feels like sitting on a hatchet.
You may need longer than a week since you haven't ridden for longer, but to be honest I think two weeks should cover it.
Winter riding is much less about badassery and much more about bundle-uppery. - malkin
1995 Kona Cinder Cone commuterFrankenbike/Selle Italia SLR Lady Gel Flow
2008 white Nakamura Summit Custom mtb/Terry Falcon X
2000 Schwinn Fastback Comp road bike/Specialized Jett