Yesterday, I was swimming with my eyes shut and I crashed into the side of the pool and hurt my head.
I wanted to tell my friend this but I stumbled a bit and said:
"Estaba nadando con los ojos cerrados y me estrellé con la borde de la piscina y me lastimé la cabeza."
Should I have used "choqué con/choqué contra"? Is estrellarse contra ok or is it estrellarse con?
Perfect! You can use either word, but why would you want to swim with your eyes closed?
Sorry, I missed the last part of your question.
I would say, "choqué con" .... "estrellarse contra"