Does hydrogen peroxide damage your hair at all?

I’ve recently gotten highlights, but they didn’t give me enough and I want my hair to be a little bit lighter. I can’t got back to the salon for at least a month, so I bought a bunch of lightening shampoos/conditioners to lighten my hair in the meantime. Then I saw this Sun In stuff thats basically just hydrogen peroxide, and I want to try it. I’m not worried about brassiness because I have violet shampoo for blondes to get rid of it. So, would using Sun In or spraying a mist of hydrogen peroxide on my hair damage it?

Also, isn’t peroxide just water with an extra molecule or something? Wouldn’t that not damage my hair because it would be like putting water in it?