I use to have issues with porcupines all the time with one of my german shorthairs. The male I had got quilled 5 times while out hunting, every time worse than the last. The last time they had to pull over 200 out of his mouth just to tube him. He had well over a thousand that time. There is no reason to cut them off, they do not deflate. They are like scales on a fish, run your hand down one way they are smooth, run it the other way the "scales" start to stand up offering resistance making it harder to pull out. Sometimes it is easier to push/pull them through if you can feel them on the other side already. Although it is very hard to find all of them it can be deadly to the dog if you leave any in. They will migrate under the skin finding there way to any number of areas. Was told by one vet of a dog having a quill make its way to its heart, hence killing the dog.