I just had a surgery and have a long scar as surgery mark. what is the best medicine or product (e.g.: lotion, oil, etc.) to eliminate this scar mark?

Too early to worry: New scars usually appear more reddish and may still have underlying swelling. Most surgical scars fade in color and diffuse down to the level of normal skin. It may take months, but eventually gets better in appearance. You may want to use vitamin E creams which may help. A scar may turn into a keloid or hypertrophic scar which can be difficult to treat. Scars can be revised by a plastic surgeon.

None: Nothing will "eliminate" a scar but you can care for it in a way to maximize the chance of a good scar. Minimize sun exposure to the scar, moisturizer your skin and things will be ok.