What financial damages did you suffer because of this? You can only sue people for quantifiable monetary damages. Did you go to the hospital? All you'd be able to receive from them if you even won your lawsuit (which you might not if the release you signed is legal) is compensation for your medical bills and lost wages.
It doesn't even sound like you missed any work or even went to the emergency room, so what financial losses would you be suing them for, exactly? The cost of repairing the small hole in your desk?
Also, as you admit, YOU stupidly touched the acid after seeing it burned your desk, so there's a lot of factors working against you. I just wouldn't do business with them again and leave it at that.
Oh and the next time you see some substance eating away at your desk or anything else, you might not want to touch it.

