You cut yourself and use a drop of your own blood to heal someone else.  You take 1d4 necrotic damage.  This damage can't be reduced in any way.  Choose a creature within range.  That creature regains hit points equal to 3 plus your spellcasting ability modifier, plus the amount of damage you dealt to yourself using this spell. 

At Higher Levels.  The amount of healing done with this spell increases by 1 at 5th level, 11th level, and 17th level.  At 11th level, the damage dealt to yourself increases by 2d4.  You can fine-tune the amount of d4s used in damaging yourself, which also affects how much healing you'll give with this spell.