Uneven skin tone is caused by pigmentation on the skin, which can be due to over sun exposure, hormonal issues, and potentially what we're using on the skin. These issues cause a level of oxidation which creates dark marks on the skin.
Now, what has worked great for me is my natural formulation, which I use with coconut oil and Shea butter with frankincense and lavender. It's important to get the formulations right.
My product is EU safety approved and we use the same formulation for every line of natural products. If you use a natural emollient, even if it's basic; virgin coconut oil mixed with Shea butter, you'll find that slowly but surely you can begin to even your skin tone.
To fix an uneven skin tone, it's important to have a level of SPS protection and a natural solution would be to use raspberry seed oil. Now, raspberry seed oil can protect the skin and you can add that to your natural emollient.
There are no adverse effects on using that day by day. But watch the video that I have uploaded on YouTube called "What the Health Next" (below) -- that will give you some information and a lot of insight into how sunscreens can cause more harm than good.