Sorry if I'm not answering your question but as a single mother I can't help but make the following points:
It is completely unfair that you have not been able to be a part of your childs life, I'm sorry that things turned out this way. As the childs father, you do have rights and can go to court for visitation rights or even shared custody. This is your son, of course you can be a part of his life if you want to.
No matter what happens you will always be his biological father and play a crucial role in his life, even if absent: he wil grow up wondering about you, asking questions about his daddy and probably want to meet you at some stage if he thinks you are alive.
I'm in no way trying to make you feel guilty, I just want to give you his side of the story and make you aware of all your options.
If you want nothing more to do with him then that's perfectely ok but if you decide that maybe you would like to be a part of your little boys life then you can use the polish courts to negotiate access/part custody to your son. It's only fair.
Good luck!