Boot blisters

Hi guys—I’m in my second season of boarding and decided to buy some boots because renting adds up. I ended up choosing some highly-rated K2 boots. Today was the first day I used them, and they felt great for a few hours, but then the J bars ended up giving me wicked blisters near the end of the day. I’ve never had boots with J bars, so is this just normal breaking-in process and I’m overthinking it, or should I be worried?? Not sure if I can return them.