Keeps falling back.

So we are currently at the crawler/cruising stage with our 9 month old. He is still a little wobbly, so he ends up falling back and hits the back of his head quite often. We have wood floors. Will this affect him if jt keeps happening to him? Idk what signs to look for 😣 would itt be the same as a concussion? This happens maybe 2-3 tmes a day... He is such an explorer and i don't want to have to put a playpen + mat around him but I will if i have to for his safety.