Paracetamol is extremely toxic in case of overdose, and the lethal dose is quite low so it is possible to overdose if you take too many pills in a short interval of time. If by long term toxicity you mean taking a low dose of paracetamol everyday for example there is an increased probability of toxicity. But generally speaking if the dose is low there shouldn't be much of an effect. Its only toxic after surpassing the limit your liver can process. There are substances that are immediately tox at any dose, lead for example. Other are only really affecting you negatively only after a certain dosage, being harmless before arriving at that point