Crib bumpers

You should only use mesh ones. All other ones are not safe.

but she is hitting her head on a hard surface?

The use of any crib bumpers are not safe, they’re a suffocation hazard. The alternative is putting her in a bassinet with mesh sides

she will be okay. Babies are resilient.

You shouldn't use crib bumpers, even the mesh ones are considered iffy.
Does she hit hard? Does she cry? You could try talking with the pediatrician to see if they have any recommendations.

You really shouldn't use any

she hits it hard enough it leaves a mark

she will be fine. they hit their heads quite a bit as they become mobile. she will learn to not smack into the wooden bars. it’s all apart of learning.
the bumpers, even mesh, have high risk of suffocation and strangulation. just let them learn by doing.

My kids have a wooden crib as well. I did not use the crib bumpers. But I’ve noticed my girl hitting her head a little as well. But as she grows it won’t be a problem

Maybe you could wrap each bar with something? Like have padded sleeves made that velcro on? That way you don't have a bumper that poses a suffocation risk but you're still padding the bars.

Something like this https://www.etsy.com/listing/1301560819/ladder-bar-covers-rung-pad-tubular

Or this https://a.co/d/5wHeA4V