Where do you live that you feel you need to carry a knife to feel safe? Unless you're Steven Seagal, pulling out a knife in a volatile situation is more likely to get you injured than anyone else , as soon as you lose control of that knife (Which you will), whoever you're fighting now has a knife and you don't Why you think cops don't take guns into prisons? Take boxing classes or learn to fight instead
I do agree. To that: "Knife should be felt, not seen." That means, you do not pull and show it till moment it is to be used. If possible, pulled in very second of being used to give no chance to react. Showing knife/gun may save ones ass from confrontation today, but attacker may decide to "up their game" for next time and not give you chance to react.
I think if you're worried about encountering the same attacker again...who learns from your mistakes...I think you need a lifestyle change.