Where did you get the dult from?
Did you catch it yourself?
I would certainly not release it back. It´s been in contact with other amphibians from a different origin, the risk of introducing patogens into the wild populations is no joke.
The way to go would be taking it to SEPRONA (or your portuguese equivalent) so that they can handle the situation.
And please....in the future, don´t catch or support the illegal collection of our native animals...it´s just wrong.