I cut my finger last night with a knife. my finger is numb tingly and when i put my hand below my heart it feels like my finger is getting shocked

Nerve laceration: or partial injury can make an area feel numb and change when there is more swelling. A bruise may also be more symptomatic to a nerve woth increaed blood and swelling. Gravity helps put more blood in exacerbating swelling, thats why it feel better to elevate, so do so! and follow up for an evaluation wrt the laceration, including assesment of sensataion and motion