Hi there and thank you for your question,
I will try to assist you with your legal question but please feel free to ask as many follow up questions as you like until you are 100% satisfied.
I think that those two things are actually completely different.
Patent infringement is when a person has a registered patent (i.e. a method of doing something, like a way of manufacturing a table, or whatever) and you copy that method in order to make your own product which you then sell. The infringement aspect is that you can't copy the same WAY that they are making their thing. The easiest example is in pharmaceutical drugs where there is a certain formula and way to mix the drugs. You can't copy that formula or way to mix the drugs.
Counterfeit goods and/or passing off is when you've had goods manufactured with another companies logo on the goods, or designed in such a similar way that members of the public think that your goods are actually the real thing. e.g. you sell shoes with the Nike tick on it, making people believe that they are "real" Nike shoes. If the goods are identical, then it would be guilty of selling counterfeit goods. If the goods are differently designed by using the Nike logo, then is it passing off.
Does that make sense?
Either way, you might not be allowed to sell the stock and you may need to actually destroy it!
But once it has been sold, it's been sold ...
If my answer hasn't answered all of your questions, please send me a REPLY with follow up questions so that I can continue to assist you in this same thread for as long as you need. Let me know if you need more advice - dont just rate my answer as "bad".
If my are HAPPY with my answer then please click one of the STAR ratings or the SMILEY FACES to rate my answer!
Good luck and best regards,