In my opinion you ignore it. Being in PA for your son's medical care was a temporary absence from your NJ home, like being in the hospital or being away on vacation. You were a NJ resident all year. You were never a PA resident.
If you worked in PA, or had any other income from PA, post the details and we'll tell you how to handle it. Otherwise, I would just ignore the stay in PA and file your tax returns as if you were in NJ all year.
