Why not just listen to your doctor?
There are lots of marks, bumps, and warts that appear on a human body as we age. Most of them are benign, a natural part of aging. Of course it is a good idea to get a medical opinion of anything that changes.
If if a medical professional tells you it is OK, than it is almost certainly OK (sure, there are horror stories on the internet, but they are the exceptions. 99.9% of the time the doctors get it right). There is nothing wrong with getting a second opinion, but if the second opinion agrees with the first then you really should listen to the doctors.
This is part of the reason that healthcare costs are so high.