Depending on where you are in the world, there are certain rules about fragrance and cosmetics that you need to be aware of and follow strict guidelines. Don't be naïve in thinking that the rules don't apply to you. Even if you're only creating small batches, you still need to make sure that your products are safe and compliant.
The International Fragrance Association, otherwise known as IFRA, has compliance rules that apply in many countries, especially in the EU, but also in countries like Saudi Arabia and the UAE.
EU cosmetic guidelines are even stricter about the safety of cosmetics, so if you intend to create your own fragrance and incorporate it into a product that's going to be used on the skin, you need to understand the guidelines. They will tell you which ingredients are allowed, which are restricted, which are banned and in what quantities you can use them safely.
You can visit the respective websites and figure it out for yourself or get in touch with a professional that can guide you on the right path. Your products will also need to be tested by a cosmetic chemist before you can legally sell them.
The world is a very litigious place these days and the last thing you need is to get sued by a client for a reaction that they had to your product.