I read that the chemicals potassium hydroxide and sodium hydroxide are extremely corrosive and will cause severe burns but I also see videos of people saying that if you get lye on you, then just wash it off and you’ll be fine. Is that actually ok. The fact that the stuff is sold in hardware stores makes it seem even less dangerous than the warnings make it out to be. Which is it?
As noted in the comments, lye burns are very damaging to skin and especially mucous membranes. This damage can be drastically reduced if the lye is washed off as quickly as possible.
One reason that these solutions are considered particularly dangerous is that there is no discomfort immediately upon contact (in contrast to acids, which tend to produce burning sensations immediately). Instead, the affected surface simply feels a bit soapy. As a result, the presence of lye on skin may not be noticed until it is too late to prevent damage by washing.
On a side note, the "it's sold in hardware stores" argument is not a good test for chemical toxicity. There are numerous highly toxic chemicals that can be purchased readily.
This is a purely anecdotal example: I once set up a target at a shooting range which involved mixing lye. My hands were damp because I had just wiped off some snow, which provided a tacky surface for some lye to stick against.
About 2-3min later, it itched. About 10min later, it felt like an open wound, because it was; the skin had turned into a "soup" about the size of a penny. I rinsed with soap and water, added a bandage; I have a scar now.
TLDR it's definitely bad for skin.