Don't be concerned at all. The surface wood fibers are the only ones affected by your washing. Any sanding done to finish the floor will remove the affected fibers along with...hopefully...any water staining that you may have caused.

Thanks, that's a relief! Is this the case even if water dripped into the gaps between boards?

Yes, you will not be able to see any 'damage' the water may have done to the board edges. If you can't see it from a standing position on normal room light, it really is of no consequence.

I was thinking more about the wood absorbing the moisture and cupping/warping. But it sounds like I probably didn't use enough to make that an issue.