Such type of brown mark can be a lentigo or lentigene. Lentigo are flat brown lesions which do not darken following sun exposure and what you are having on face may be solar lentigo which is less than 5mm in diameter and irregular in shape but they may merge to form larger spots.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.
Thank you so much for taking the time to respond. I wouldn't call it a "lesion" and it is not on my face. It is a small "birthmark" like spot on my HAND...It is flat, without any pain...It has actually lightened up since I posted this...I can still faintly see it though...