Experience on the battlefield doesn't mean experience with healing injuries, but he'll look at Sansa's anyway, because she's right, he has seen plenty of them before. It looks clean and the bleeding has mostly stopped, both of which are good signs.

"That one should be fine until someone with healing skill can look at it." Which he will insist on, even if Sansa doesn't.

"Both of you are going to want to be as careful as you can of them until they're healed."