Worse case scenario someone will see your head I would just leave it.

Well, all you need is too replace the glass with non-see through. I don't know if the film/sprays will work in a shower.

Patricia is right. No need to do anything because unless someone can climb up and look down into the shower they're not going to see anything.

How high is the window off the ground? Can neighbors see in from their homes? Go outside and see how much you can see. Is this a high-rise with other apartments right across from you?

During the day there is a reflection on the glass from outside so no one can see in. At night would be the time (when it's dark outside but light inside) when a peeper could see. So you only need a privacy fix at night (assuming someone can actually get a view in your window).

So sunlight can come in during the day--no problem.

i spray frosted the glass door panels that connect my bathroom to my pool area several years ago. it has held up great. the spray frost is in the spray paint aisle of your local hardware store for only a couple of bucks. if you don't like it, simply scrape it off with a razor.