Yes that was what it did, but how did it do it?
Magic
Ha ha what gave it away? lol. I'm guess that it either dulled the pain or dulled Harry's awareness of the pain or caused Bonnie to "sleep" or in some way settle down.
I thought of it like an epidural. He was going through labor, after all.
But a magical one ... Like I said, once he was cut off from Winter magic, she was able to interact.
I agree. Harry remarks how cold it felt, which is a pretty big sign. I wouldn't be surprised if it was similar to the painkiller effects of the Winter Knight's mantle.