The thing is, I can't see how that'd happen based on my understanding of how acids and plastic work. It isn't like there's a good layer of plastic on top of a skunky layer that has been exposed.
e.g., plastic is made of oil, which is formed into polymers out of smaller monomers. Much of it is chemically inert, it's why your gas can is plastic or isopropyl alcohol or... But some (if you want to see through them) aren't, and if you expose them to acids two things can happen: attack & absorption.
Plastics Chemical Resistance Chart | Plastics International
Attack basically means it starts breaking apart the polymers, and absorption means the plastic might pull the substance into it. However it's like dropping gold or something into an acid-bath -- the acid bath will have gold in it, but it isn't like the gold will now start leaching into water because of it.
I hope you mean tank, not that you dumped it back into the bottle of eliquid that it came from. I wouldn't vape that then, you wouldn't die but I'm not 100% sure what the acid broke that plastic down into -- but that's where I err on the side of caution.