[Healeys] paint question

[David Z]

I made a third brake light for my car and temporarily attach it to the trunk
lid using a magnetic material normally used in the sign business. I've now
noticed a "blotch" on the paint that is slightly darker where the brake light
was positioned compared to the rest of the car. I've tried rubbing it out with
a 3M product to no avail. Is there anything I can do to restore the paint
short of repainting? Thanx in advance.
David Z.