Display Hit Text On Collition

Hi, I am trying to display an amount of damage dealt using text. I am working a on 2D game and when the player hits an enemy for (let's say) 2 Hp, I want to have a small red number 2 to pop up above the enemy's head and fade away. I feel like a particle system could handle this beautifully, if only you could change the particle sprite via script. If anyone knows how this could be done in c#, I would be very grateful!