I dropped something into my dashboard

Hello, sounds like the "cracks" are likely the defroster ducts of the ventilation system. The duct register is incredibly difficult to get to - you'll have to access the dashboard itself by removal, or if you're lucky, the defrost ducts might be able to be accessed underneath the dash - but this is unlikely. You'll need some professional assistance from a shop or technician near you. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops