A photo would be helpful, but an in-person evaluation is more valuable. In general, there are three reasons why the skin around the eyes can be [or seem] darker:
1. The thin eyelid skin allows the darker muscle underneath to show
2. The contrast between eyelid fat bulging, and hollowness at the orbital rim [tear trough] eyes can create a shadow effect that exacerbates darkness.
3. Skin pigmentation.
Depending on which of the above is the issue, different modalities may be helpful [time, fillers, laser resurfacing, concealer etc].
If you decide to explore this further, I would recommend consultation with an ASOPRS trained Oculoplastics surgeon. You can find one close to you on the ASOPRS dot org website.