F.W.I.W. I wouldn't count on the helmet being undamaged even if there are no visible signs on it's exterior.
Went down on my GSX1100G many years ago and never remembered hitting my head and the helmet showed no outward, visible damage.
Years later when that helmet had grown old and way tooo skanky, I cut it apart to see how it was made.
There, inside the helmet, was a spider-web cracks on the inside of the helmet and beneath it, crushed foam.
Had I hit my head again in that same spot = It would have offered no protection.
My lesson was learned that day. You go down, you throw it out. Period!