Thanks for posting the qwery.
Some lesions after surgical removal can leave behind mild scar or post inflammatory hyper or hypopigmentation
I.e. discolouration of skin.
Don't use over the counter medicines and visit a dermatologist
for proper evaluation of the mark.
Depending the depth and colour density of the scar, lightening agents can be prescribed like glycolic acid
or kojic acid etc.
With time the pigmented area will lighten up.
Hope for speedy recovery.