I spilled quite a bit of 30% NaOH on myself after learning from my chemistry textbook that you can make hydrogen gas using the amphoteric property of aluminium (honestly, would recommend, so much fun). Those burns look worse, if anything, than the ones I received, the few blisters I had looked about the same (granted, I never covered such a large area, in that region of the body).

I know it can burn you to the bone, but you'd have to stay submerged in it, for a long time. If you simply get splashed with it, and you do something about it in a relatively timely manner, you can totally get away with a dry, bleached patch of skin. It doesn't immediately melt your skin, you won't even feel the tingling/burning sensation for some ten(s) of seconds.