Ignite doesnt actually reduce healing
3 games in row i ignited enemy top laner, when he had between 50 - 10 hp (not methaphoricaly, i checked replays, max hp was 49 and lowest was 32), and he had biscuits, ate 1! and outhealed ignite. Hmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm. Reduce healing, and deals 100+ damage overtime huh?? hmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm alright then riot.... i guess thats how that works. So remember guys, if you lane vs ignite, just pop a potion when you are at 1hp, you will safely out heal it :)[slayer-jinx-unamused]
heals a small amount when consumed on top of healing masteries when low if they were using then in that game. So at low levels it is hard to kill someone with ignite even with the Grievous wound on them.