Thanks for posting your query.
The dark painless spot can be a mole.
A mole if increasing in size it can be a malignancy also.
Another possibility of such lump is a neurofibroma
You should get yourself examined by a physician of your locality and get investigated if needed.
I hope this answers your query.
In case you have any follow up queries or doubts, you can forward them for me, and I shall be glad to help you.
Please accept my answer in case you do not have further queries.
Wishing you good health.