I had a safety talk by a man who was severely burned by sulfuric acid over a large portion of his body. He was delivering it into a tank and a valve broke, exposing him to the acid.
When it makes contact with water, it heats up (heat of solution) so there is the chemical damage and the simultaneous chemical interaction with flesh.
I’ve seen acid attacks depicted as a form of torture in prisons. I can’t imagine there are many places to get the acid in Nicaragua. It’s a very inhumane action against the priest, certainly, and against the Church.