He might be shocked at first. Naruto is used to seeing Kurenai as an ally, so being hurt by her would be unexpected. He could immediately ask her why she did it. If it was a serious injury, he might struggle to stay conscious while trying to understand the situation.
In some cases, Naruto could be deeply hurt and withdraw from Hinata. He might question their relationship and whether he misjudged her all along. If the hurt is physical, he may also be more cautious around her in future interactions. For example, if she accidentally used a strong jutsu on him during training, he might be hesitant to train with her again without proper precautions.
Sakura would probably be very angry at Kurenai. She's protective of Naruto and would demand an explanation. She might even try to heal Naruto right away if it was a physical injury.
Macgyver would probably be very worried. He'd quickly assess the situation and try to stop the bleeding if she was bleeding. He'd use his resourcefulness to make a makeshift stretcher or bandage.
Naruto might be initially shocked and heartbroken. He is someone who values loyalty and friendship deeply, so being cheated on would be a huge blow to him.
He may try to understand Boruto's reasons. Naruto has always been one to look for the good in people. So, even when hurt, he might give Boruto the chance to explain himself. He could say something like 'Boruto, I know you didn't mean it. Let's talk about what's wrong.' He'll be patient and try to resolve the issue rather than getting angry right away.
Naruto could also react with anger. He's not one to just take things lying down. If Sakura hurts him, he might lash out verbally. He could say things like 'I've always been there for you, and this is how you treat me?' expressing his frustration and pain. And then he might storm off, leaving Sakura to realize the impact of her actions.
He might be initially shocked. Naruto is used to thinking of Hana as an ally, so if she hurts him, it would be unexpected. He could immediately try to get some distance to assess the situation and figure out why she did it.
In other fanfics, Naruto might try to understand Sakura's perspective. He's a very forgiving person, so he could give her the benefit of the doubt and try to figure out what made her act in a way that hurt him. He might think that she had her reasons and try to work through it with her.
Well, the team's reaction can vary depending on the specific circumstances in the fanfiction. Sometimes they are angry, especially if they think the injury was preventable. They'll do whatever it takes to get revenge on the cause of Keith's hurt if it was due to an enemy attack. And they'll also be there for Keith during his recovery, sharing stories, and trying to keep his spirits up so he can heal faster.
He probably gets really protective. Jack might immediately rush to her side and check on her injuries. He'd be worried sick and would want to make sure she gets proper medical attention right away.