I just learned that lemon essential oil + sunlight don't mix. Apparently, any citrus essential oil can be photo toxic. So, if you make a lotion with a citrus essential oil, don't go in the sun. It can cause your skin to be more sensitive to sunlight and might cause a sunburn.
I made this mistake for my recipe for super simple homemade lotion. I really love all things lemon and I added lemon essential oil to the lotion to make it smell nice. Please forgive my mistake. It is okay in winter, but not in the warmer months.