Many moles do change over time but it is important that anything that looks different is checked out just to be on the safe side. GP's are very used to assessing moles and if they suspect something isn't right they will refer on to the dermatologist (skin specialist).
You can read more about getting your mole checked by your GP.
I hope this helps. Give us a ring if you would like to talk anything over The number to call is Freephone 0808 800 4040 and the lines are open from 9am till 5pm Monday to Friday.
