Did you turn the camshaft sprocket by hand? If so, I don't think you could bend any valves without noticing. Even with a wrench, the substantial extra work of doing the bending should be noticeable.

Checking valve clearances should show a bent valve, the clearance will be too large. But if you haven't adjusted your valves in 11 years, then ????

Sometimes my spark plugs do that too. Scary the first time, but use a steady hand on the wrench & don't apply any bending to the socket extension.