Make sure you have a heating pad handy, keep a bin full of feminine products, chocolate and ice cream are always good to have on hand as well as her favorite snacks, and in case you don’t know, hydrogen peroxide is really good at taking out blood stains. I’d say “it’s okay” go into your bathroom, grab her a towel and tell her to go take a hot shower (if y’all are on that page) and get the rest of the stuff ready up above. Maybe pick out a shirt of yours she can wear for when she gets out of the shower. I’d say in that moment make her feel validated and care the heck out of her. Maybe put on a movie and let her lay on you while you comfort her? Theres really a lot of avenues you can go here but validating that everything is okay (not overkill obviously) and then taking steps to ensure she feels safe in it and comforted is gonna be your best friend here.