Baby keeps hitting himself.

I don’t know what to do, my 8 month old won’t stop climbing on everything, he ends up falling down and hitting himself, you would think after the first or second hit he would relax but he doesn’t. He climbs on the baby gates, the crib rail, the playpen and so on. The only place he hasn’t hit himself is in the high chair but he has tried to get out of there too by pulling his leg out (he was strapped on tho). I can’t watch him every second nor can I keep pulling him off of the rails every time he climbs up to hold on because he will go back on the second you take him off. I don’t know what to do. I’m worried about his little head that keeps taking the falls. I’m so stressed out, no where is a safe place for him because he is constantly finding a way to get himself out of things.