Is it ok to remove pork and eat food?

Asalaam alaikum, I went to Subway today and got a Steak and spicy chorizo sandwich. I was recommended it by a muslim friend, and when i asked him if spicy chorizo was halal, he said it was just meat. However, once I got back to my desk and had a bite, I quickly googled it - just to double check and to my surprise, I learnt spicy chorizo is actually pork.. I then removed the spicy chorizo and carried on eating half of the sandwhich, but then I thought this is wrong and now feel extremely guilty. You surely still can't eat something which had pork in it before? My two questions for the forum: 1.) Are you able to eat food which had pork in it (pork was removed). 2.) what do I have to do to in order to attempt to gain forgiveness for eating pork? Thanks for your time, I look forward to hearing from you.