Hair texture without shampoo

Hello everyone.

I think I am ruining my hair because I use shampoo everytime I take a shower. I do that because my work is not clean, but mainly because my hair will have a very weird texture if I don't shampoo, like the old dolls' hair.

So what are my options?

P.s. lately I am having pimples/acne in my scalp Does that have to anything with it?

Thank you.