I have a dark mole like skin patch near my lower triceps. Can I use Differin gel to remove it? (photo)

Hi, I know of sure that it is not a mole from my birth. However, I don't exactly know when it appeared but according to my parents it showed up when I was about 12 years old. I was in Nepal at that time. The doctor there said not to be too concerned about it, then I moved to Holland and I have not questioned about it or discussed with a doctor. After reading some articles on the internet, I wanted to show it to a professional before going to the dermatologist. Sorry if my English is bad.