Wooden bridges are deathtraps. The slime that builds up on them can be
a terror as well. Last fall I took a spill on one due to similar loss
of traction. One second I was spinning nicely, the next I was laying on
my hip going WTF?? I got a hip bruise and lost a couple nice old
Cinelli end plugs. Damn you bridge!

Now I slow down and only coast across wooden bridges unless I'm
positively sure they're dry.

You'll heal up fine. I've taken a couple to the face, including going
headfirst into a snowbank at night, losing my glasses in the snow, and
having to ride home, one-handed to keep the blood from gushing out my
eyebrow. Fun for all! Commuting as extreme sport! w00t!