How to lighten dark spot between eyebrows? (Photos)

From your description, it sounds like you have developed prolonged post-inflammatory hyperpigmentation as a result of the trauma sustained from repetitive shaving of the unibrow. This phenomenon can occur in anyone, but is much more common in skin of color. owing to the greater background pigmentation. Regular at-home treatments using topical prescription-strength skin bleaching agents, such as hydroquinone, arbutin, kojic acid, retinoids and topical corticosteroids can be helpful for fading this problem. Typically prolonged treatment periods (several months) are required accompanied by diligent sun protection in order to achieve gratifying improvement. Fading may be further hastened via the adjunctive use of in-office, superficial peels consisting of high concentration glycolic acid, Jenssner's solution, high concentration salicylic acid or low strength TCA. Combining the latter with medical microneedling using a Dermastamp and the application of topical transexamic acid may provide additional benefit and hasten improvement. Be wary of fraxel laser and other light-based therapies as these themselves have been associated giving rise to prolonged postinflammatory hyperpigmentation and even permanent hypopigmentation particularly in skin of color.  You would be wise to seek consultation with a board certified aesthetic dermatologist. Best of luck.

Good Morning.  You might want to try a product called Hydroquinone.  Check with your local doc.  It comes in different percentages.  I routinely prescribe it at 10% to use twice a day for as long as you want. 

Thanks for your question. It is common for people to develop pigmentation changes in areas of repeated or prolonged inflammation and so this could possibly be related to shaving. However, there also seems to be similar skin changes on your forehead and the dorsum of your nose. Is this the case or is the photo?
There are a number of treatment options available to you, but I would normally recommend the use of topical hydroquinone. This is a excellent treatment for pigmentation changes but you need to see an experienced doctor to devise an individual treatment plan.
Good luck
Dr Chris Macdonald