Not a skin cancer
Thanks for writing in to us.
I have read your query in detail and seen accompanying picture.Hyperpigmentation
occurs as brown macules or patches, often with a poorly defined border, irregular in outline and usually with little surface change. This is what seems to have happened in your case. This is usually related to an inflammatory condition including simple injury
to the area which might have occurred about two years back.
This does not look like a skin cancer. However you may consult a dermatologist
to confirm diagnosis and get any necessary clinical tests after clinical examination. Resolution of such problems may take a long time even with treatment.
Hope your query is answered.
Do write back if you have any doubts.