Early in the game if you need a way to heal yourself from Poison, purchase the Finger Seal from Twin Maiden Husks at Roundtable Hold. Brother Corhyn sells the Cure Poison spell (Incantation). Allocate 10 skill points into Faith to use the Finger Seal and in the Memorize Spell menu at a site of grace, equip the Cure Poison Incantation. Equip the Finger Seal and cast with left or right hand.