It's normal for balms to go grainy because of sudden temperature changes. It doesn’t affect the quality or the potency of the product. When balms are exposed to warmer temperatures, the butter's natural fatty acids melt at a different rate than the rest of the fats and waxes in the balm. Whereas when the temperature cools again, these oil droplets recrystallize, causing lighter colored hard grains to form on the surface of the balm. The top layer can also condense and appear like a white film.