I sprayed the toilet with a sprayer with a very high concentration of potassium permanganate, and I

If you want to disinfect the bathroom, in fact, you don't need such a high concentration of KMnO4 solution, the concentration is up to 3% 4% is enough, of course, it is safer to wear a mask, after all, potassium permanganate is a strong oxide, so wearing a mask is better than not wearing a mask, potassium permanganate can cause respiratory tract damage after inhalation, concentrated solution or crystals are corrosive to the skin, irritating to the tissues, therefore, it is recommended that when "defending" the bathroom, also do a set of full-body protective clothing (dust masks, anti-gas clothing)

It is not poisonous, but the skin and oral mucosa may be corroded and peeled off, which is equivalent to skin removal.

Of course it's possible. If you don't use a sprayer, it's safe.