Look, I don’t want to be mean, but Halsin, Nere, Minthara, and anyone acquainted with the Shadowcursed lands will tell you it’s not a good place to be. You don’t have to use torches, just have a light source. There’s a weapon in the Temple of Lathander that gets you one, or you can use spells.
My advice is to rendezvous with the Harpers ASAP and get ready for a fight. When you are ready to fight, speak to the Cleric on the top floor of Last Lighy to get a blessing that protects you from the lesser Shadowcurse. Keep the cleric safe at all costs. Then ambush the Drider to get a pixie for greater protection.