Lissandra's Passive rework concept

Passive-Chilblain: No longer periodically refunds mana. NEW: Enemy champions hit by Lissandra's abilities become Chilblained for 1.5 seconds.

Lissandra's spells abilities against chilblained champions deal bonus magic damages equal to 25% of the last damage instance that struck them over 2.5 seconds (1 tick of damage every 0.5 seconds) and refreshes the debuff duration.

Applying Chilblain again before the end of the effect will half the remaining damages from the last Chilblain and apply them instantly.

Numbers are subject to change.

Thoughts?