Some years ago i was bitten by a cat that resulted in a scar, but i experienced no pain. was i allergic to him?

Probably not: If your concern is the appearance of the scar after a cat bit chances are you were "allergic" to the sharpness of its teeth per se and not allergic to cats in general. All animal bites that puncture the skin will leave lasting scars. If it got infected as commonly happens with cat bites that could magnify the appearance of the scar.

Not likely: Cat bites can be highly contaminated wounds due to the deep inoculation of bacteria with a very small skin puncture that may interfere with the ability to adequately cleanse the wound. These are more prone to infection, compared to dog wounds, and ultimately this may lead to more extensive scarring if not properly treated. Once formed it may be difficult to improve the scar.