If it happened you were with Laxus and you got hurt with magic then he'll be the type to blame himself for not being there to protect you. Laxus would always wish if it was him who got hurt instead of you. If you continue to not give up and get rest but instead continue to fight along then he'll get annoyed and frustrated and maybe mad... (like if you don't listen to him at all and ignore his pleas that you rest and take it easy).

If your injury is super bad Laxus will personally carry you away from the danger and to a medic as soon as possible. He'll be very emotional and hopeful that you'll be okay. If you're in the bed, he'll stay by your side and wait until you're better. He will comfort you the best he can and try to cheer you up by some jokes (he can find some really good ones even if he seems like he fails at social interactions).

Once you're able to go home he'll be there for you at every step. Will constantly repeat you have rest while he does things instead of you. Laxus will do his best to cook, clean and wash whatever you need. You get to watch him work because he loves you so much he doesn't want you to get hurt more often.

+ will constantly tell you that's he's sorry for what happened and he'll say he loves you over and over again.