He's backing off a little with the honesty, seeing her get so nervous. He didn't want to scare her. It's just... hard, to have not told a single person all this time.

He nods to the first part, and to both parts he says that it wasn't even really a person - or if it was, they were deformed something awful. But he's not a very eloquent person, so any attempts to get him to describe wrong how won't get much. Just that things were all the wrong shape ('things' here meaning bodily features) and it looked real dangerous.