Rosehip oil is Rosehip seed oil. This is made by cold-pressing the seeds and is something that will have to be purchased rather than made at home.
I just re-watched the video with Marisa making the sunscreen. She misspoke! She meant to say, carrot tissue oil. The recipe is correct, you can add the carrot tissue oil and the carrot seed essential oil for added sun protection. However, this isn’t necessary if you don’t want to add it, or can’t find it.
Instead of the sesame oil, you can increase either one or a combination of the other oils in the recipe to make up for it.